CVE-2021-47512 (GCVE-0-2021-47512)

Vulnerability from cvelistv5 – Published: 2024-05-24 15:09 – Updated: 2026-08-05 08:48
VLAI
Title
net/sched: fq_pie: prevent dismantle issue
Summary
In the Linux kernel, the following vulnerability has been resolved: net/sched: fq_pie: prevent dismantle issue For some reason, fq_pie_destroy() did not copy working code from pie_destroy() and other qdiscs, thus causing elusive bug. Before calling del_timer_sync(&q->adapt_timer), we need to ensure timer will not rearm itself. rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (4416 ticks this GP) idle=60d/1/0x4000000000000000 softirq=10433/10434 fqs=2579 (t=10501 jiffies g=13085 q=3989) NMI backtrace for cpu 0 CPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 5.16.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:write_comp_data kernel/kcov.c:221 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x1d/0x80 kernel/kcov.c:273 Code: 54 c8 20 48 89 10 c3 66 0f 1f 44 00 00 53 41 89 fb 41 89 f1 bf 03 00 00 00 65 48 8b 0c 25 40 70 02 00 48 89 ce 4c 8b 54 24 08 <e8> 4e f7 ff ff 84 c0 74 51 48 8b 81 88 15 00 00 44 8b 81 84 15 00 RSP: 0018:ffffc90000d27b28 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888064bf1bf0 RCX: ffff888011928000 RDX: ffff888011928000 RSI: ffff888011928000 RDI: 0000000000000003 RBP: ffff888064bf1c28 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff875d8295 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880783dd300 R14: 0000000000000000 R15: 0000000000000000 pie_calculate_probability+0x405/0x7c0 net/sched/sch_pie.c:418 fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:383 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 run_ksoftirqd kernel/softirq.c:921 [inline] run_ksoftirqd+0x2d/0x60 kernel/softirq.c:913 smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 </TASK>
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-06-17 17:36 UTC
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: ec97ecf1ebe485a17cd8395a5f35e6b80b57665a , < 2a51edaf5cc563574878b93d7ef3d5955dda7030 (git)
Affected: ec97ecf1ebe485a17cd8395a5f35e6b80b57665a , < d86216dfda7c98375f809e26a30bfdaaba21d46e (git)
Affected: ec97ecf1ebe485a17cd8395a5f35e6b80b57665a , < 61c2402665f1e10c5742033fce18392e369931d7 (git)
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Linux Linux Affected: 5.6
Unaffected: 0 , < 5.6 (semver)
Unaffected: 5.10.85 , ≤ 5.10.* (semver)
Unaffected: 5.15.8 , ≤ 5.15.* (semver)
Unaffected: 5.16 , ≤ * (original_commit_for_fix)
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fq_pie: prevent dismantle issue\n\nFor some reason, fq_pie_destroy() did not copy\nworking code from pie_destroy() and other qdiscs,\nthus causing elusive bug.\n\nBefore calling del_timer_sync(\u0026q-\u003eadapt_timer),\nwe need to ensure timer will not rearm itself.\n\nrcu: INFO: rcu_preempt self-detected stall on CPU\nrcu:    0-....: (4416 ticks this GP) idle=60d/1/0x4000000000000000 softirq=10433/10434 fqs=2579\n        (t=10501 jiffies g=13085 q=3989)\nNMI backtrace for cpu 0\nCPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 5.16.0-rc4-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\nCall Trace:\n \u003cIRQ\u003e\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106\n nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111\n nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62\n trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]\n rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343\n print_cpu_stall kernel/rcu/tree_stall.h:627 [inline]\n check_cpu_stall kernel/rcu/tree_stall.h:711 [inline]\n rcu_pending kernel/rcu/tree.c:3878 [inline]\n rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597\n update_process_times+0x16d/0x200 kernel/time/timer.c:1785\n tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226\n tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428\n __run_hrtimer kernel/time/hrtimer.c:1685 [inline]\n __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749\n hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811\n local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]\n __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103\n sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097\n \u003c/IRQ\u003e\n \u003cTASK\u003e\n asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638\nRIP: 0010:write_comp_data kernel/kcov.c:221 [inline]\nRIP: 0010:__sanitizer_cov_trace_const_cmp1+0x1d/0x80 kernel/kcov.c:273\nCode: 54 c8 20 48 89 10 c3 66 0f 1f 44 00 00 53 41 89 fb 41 89 f1 bf 03 00 00 00 65 48 8b 0c 25 40 70 02 00 48 89 ce 4c 8b 54 24 08 \u003ce8\u003e 4e f7 ff ff 84 c0 74 51 48 8b 81 88 15 00 00 44 8b 81 84 15 00\nRSP: 0018:ffffc90000d27b28 EFLAGS: 00000246\nRAX: 0000000000000000 RBX: ffff888064bf1bf0 RCX: ffff888011928000\nRDX: ffff888011928000 RSI: ffff888011928000 RDI: 0000000000000003\nRBP: ffff888064bf1c28 R08: 0000000000000000 R09: 0000000000000000\nR10: ffffffff875d8295 R11: 0000000000000000 R12: 0000000000000000\nR13: ffff8880783dd300 R14: 0000000000000000 R15: 0000000000000000\n pie_calculate_probability+0x405/0x7c0 net/sched/sch_pie.c:418\n fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:383\n call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421\n expire_timers kernel/time/timer.c:1466 [inline]\n __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734\n __run_timers kernel/time/timer.c:1715 [inline]\n run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747\n __do_softirq+0x29b/0x9c2 kernel/softirq.c:558\n run_ksoftirqd kernel/softirq.c:921 [inline]\n run_ksoftirqd+0x2d/0x60 kernel/softirq.c:913\n smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164\n kthread+0x405/0x4f0 kernel/kthread.c:327\n ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295\n \u003c/TASK\u003e"
        },
        {
          "lang": "es",
          "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: net/sched: fq_pie: previene el problema de desmantelamiento Por alguna raz\u00f3n, fq_pie_destroy() no copi\u00f3 el c\u00f3digo de trabajo de pie_destroy() y otras qdiscs, causando as\u00ed un error dif\u00edcil de alcanzar. Antes de llamar a del_timer_sync(\u0026amp;q-\u0026gt;adapt_timer), debemos asegurarnos de que el temporizador no se rearme solo. rcu: INFO: rcu_preempt se bloque\u00f3 autom\u00e1ticamente en la CPU rcu: 0-....: (4416 ticks this GP) idle=60d/1/0x4000000000000000 softirq=10433/10434 fqs=2579 (t=10501 jiffies g=13085 q=3989) NMI backtrace for cpu 0 CPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 5.16.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace:  __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097   asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:write_comp_data kernel/kcov.c:221 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x1d/0x80 kernel/kcov.c:273 Code: 54 c8 20 48 89 10 c3 66 0f 1f 44 00 00 53 41 89 fb 41 89 f1 bf 03 00 00 00 65 48 8b 0c 25 40 70 02 00 48 89 ce 4c 8b 54 24 08  4e f7 ff ff 84 c0 74 51 48 8b 81 88 15 00 00 44 8b 81 84 15 00 RSP: 0018:ffffc90000d27b28 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888064bf1bf0 RCX: ffff888011928000 RDX: ffff888011928000 RSI: ffff888011928000 RDI: 0000000000000003 RBP: ffff888064bf1c28 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff875d8295 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880783dd300 R14: 0000000000000000 R15: 0000000000000000 pie_calculate_probability+0x405/0x7c0 net/sched/sch_pie.c:418 fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:383 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 run_ksoftirqd kernel/softirq.c:921 [inline] run_ksoftirqd+0x2d/0x60 kernel/softirq.c:913 smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295  "
        }
      ],
      "id": "CVE-2021-47512",
      "lastModified": "2025-01-06T20:44:28.273",
      "metrics": {
        "cvssMetricV31": [
          {
            "cvssData": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 5.5,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
              "version": "3.1"
            },
            "exploitabilityScore": 1.8,
            "impactScore": 3.6,
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      },
      "published": "2024-05-24T15:15:12.487",
      "references": [
        {
          "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "tags": [
            "Patch"
          ],
          "url": "https://git.kernel.org/stable/c/2a51edaf5cc563574878b93d7ef3d5955dda7030"
        },
        {
          "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "tags": [
            "Patch"
          ],
          "url": "https://git.kernel.org/stable/c/61c2402665f1e10c5742033fce18392e369931d7"
        },
        {
          "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
          "tags": [
            "Patch"
          ],
          "url": "https://git.kernel.org/stable/c/d86216dfda7c98375f809e26a30bfdaaba21d46e"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Patch"
          ],
          "url": "https://git.kernel.org/stable/c/2a51edaf5cc563574878b93d7ef3d5955dda7030"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Patch"
          ],
          "url": "https://git.kernel.org/stable/c/61c2402665f1e10c5742033fce18392e369931d7"
        },
        {
          "source": "af854a3a-2127-422b-91ae-364da2661108",
          "tags": [
            "Patch"
          ],
          "url": "https://git.kernel.org/stable/c/d86216dfda7c98375f809e26a30bfdaaba21d46e"
        }
      ],
      "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "vulnStatus": "Analyzed",
      "weaknesses": [
        {
          "description": [
            {
              "lang": "en",
              "value": "NVD-CWE-noinfo"
            }
          ],
          "source": "nvd@nist.gov",
          "type": "Primary"
        }
      ]
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/sched/sch_fq_pie.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "2a51edaf5cc563574878b93d7ef3d5955dda7030",
                    "status": "affected",
                    "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "d86216dfda7c98375f809e26a30bfdaaba21d46e",
                    "status": "affected",
                    "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "61c2402665f1e10c5742033fce18392e369931d7",
                    "status": "affected",
                    "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "net/sched/sch_fq_pie.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "5.6"
                  },
                  {
                    "lessThan": "5.6",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.10.*",
                    "status": "unaffected",
                    "version": "5.10.85",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.15.*",
                    "status": "unaffected",
                    "version": "5.15.8",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "5.16",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "4647680F-2C60-4192-9716-F3BBCBD68B17",
                    "versionEndExcluding": "5.10.85",
                    "versionStartIncluding": "5.6",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "6664ACE2-F748-4AE5-B98B-58803B0B2C3E",
                    "versionEndExcluding": "5.15.8",
                    "versionStartIncluding": "5.11",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.16:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "357AA433-37E8-4323-BFB2-3038D6E4B414",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.16:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "A73429BA-C2D9-4D0C-A75F-06A1CA8B3983",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.16:rc3:*:*:*:*:*:*",
                    "matchCriteriaId": "F621B5E3-E99D-49E7-90B9-EC3B77C95383",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.16:rc4:*:*:*:*:*:*",
                    "matchCriteriaId": "F7BFDCAA-1650-49AA-8462-407DD593F94F",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fq_pie: prevent dismantle issue\n\nFor some reason, fq_pie_destroy() did not copy\nworking code from pie_destroy() and other qdiscs,\nthus causing elusive bug.\n\nBefore calling del_timer_sync(\u0026q-\u003eadapt_timer),\nwe need to ensure timer will not rearm itself.\n\nrcu: INFO: rcu_preempt self-detected stall on CPU\nrcu:    0-....: (4416 ticks this GP) idle=60d/1/0x4000000000000000 softirq=10433/10434 fqs=2579\n        (t=10501 jiffies g=13085 q=3989)\nNMI backtrace for cpu 0\nCPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 5.16.0-rc4-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\nCall Trace:\n \u003cIRQ\u003e\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106\n nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111\n nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62\n trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]\n rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343\n print_cpu_stall kernel/rcu/tree_stall.h:627 [inline]\n check_cpu_stall kernel/rcu/tree_stall.h:711 [inline]\n rcu_pending kernel/rcu/tree.c:3878 [inline]\n rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597\n update_process_times+0x16d/0x200 kernel/time/timer.c:1785\n tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226\n tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428\n __run_hrtimer kernel/time/hrtimer.c:1685 [inline]\n __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749\n hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811\n local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]\n __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103\n sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097\n \u003c/IRQ\u003e\n \u003cTASK\u003e\n asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638\nRIP: 0010:write_comp_data kernel/kcov.c:221 [inline]\nRIP: 0010:__sanitizer_cov_trace_const_cmp1+0x1d/0x80 kernel/kcov.c:273\nCode: 54 c8 20 48 89 10 c3 66 0f 1f 44 00 00 53 41 89 fb 41 89 f1 bf 03 00 00 00 65 48 8b 0c 25 40 70 02 00 48 89 ce 4c 8b 54 24 08 \u003ce8\u003e 4e f7 ff ff 84 c0 74 51 48 8b 81 88 15 00 00 44 8b 81 84 15 00\nRSP: 0018:ffffc90000d27b28 EFLAGS: 00000246\nRAX: 0000000000000000 RBX: ffff888064bf1bf0 RCX: ffff888011928000\nRDX: ffff888011928000 RSI: ffff888011928000 RDI: 0000000000000003\nRBP: ffff888064bf1c28 R08: 0000000000000000 R09: 0000000000000000\nR10: ffffffff875d8295 R11: 0000000000000000 R12: 0000000000000000\nR13: ffff8880783dd300 R14: 0000000000000000 R15: 0000000000000000\n pie_calculate_probability+0x405/0x7c0 net/sched/sch_pie.c:418\n fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:383\n call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421\n expire_timers kernel/time/timer.c:1466 [inline]\n __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734\n __run_timers kernel/time/timer.c:1715 [inline]\n run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747\n __do_softirq+0x29b/0x9c2 kernel/softirq.c:558\n run_ksoftirqd kernel/softirq.c:921 [inline]\n run_ksoftirqd+0x2d/0x60 kernel/softirq.c:913\n smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164\n kthread+0x405/0x4f0 kernel/kthread.c:327\n ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295\n \u003c/TASK\u003e"
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: net/sched: fq_pie: previene el problema de desmantelamiento Por alguna raz\u00f3n, fq_pie_destroy() no copi\u00f3 el c\u00f3digo de trabajo de pie_destroy() y otras qdiscs, causando as\u00ed un error dif\u00edcil de alcanzar. Antes de llamar a del_timer_sync(\u0026amp;q-\u0026gt;adapt_timer), debemos asegurarnos de que el temporizador no se rearme solo. rcu: INFO: rcu_preempt se bloque\u00f3 autom\u00e1ticamente en la CPU rcu: 0-....: (4416 ticks this GP) idle=60d/1/0x4000000000000000 softirq=10433/10434 fqs=2579 (t=10501 jiffies g=13085 q=3989) NMI backtrace for cpu 0 CPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 5.16.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace:  __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097   asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:write_comp_data kernel/kcov.c:221 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x1d/0x80 kernel/kcov.c:273 Code: 54 c8 20 48 89 10 c3 66 0f 1f 44 00 00 53 41 89 fb 41 89 f1 bf 03 00 00 00 65 48 8b 0c 25 40 70 02 00 48 89 ce 4c 8b 54 24 08  4e f7 ff ff 84 c0 74 51 48 8b 81 88 15 00 00 44 8b 81 84 15 00 RSP: 0018:ffffc90000d27b28 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888064bf1bf0 RCX: ffff888011928000 RDX: ffff888011928000 RSI: ffff888011928000 RDI: 0000000000000003 RBP: ffff888064bf1c28 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff875d8295 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880783dd300 R14: 0000000000000000 R15: 0000000000000000 pie_calculate_probability+0x405/0x7c0 net/sched/sch_pie.c:418 fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:383 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 run_ksoftirqd kernel/softirq.c:921 [inline] run_ksoftirqd+0x2d/0x60 kernel/softirq.c:913 smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295  "
          }
        ],
        "id": "CVE-2021-47512",
        "lastModified": "2026-08-04T10:17:06.780",
        "metrics": {
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                "privilegesRequired": "LOW",
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                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
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              "impactScore": 3.6,
              "source": "nvd@nist.gov",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Modified",
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            "type": "Primary"
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    },
    "redhat_vex": {
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      "current_release_date": "2026-08-04T19:56:05+00:00",
      "cve": "CVE-2021-47512",
      "id": "CVE-2021-47512",
      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net/sched: fq_pie: prevent dismantle issue",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47512.json",
      "version": "3"
    },
    "suse_vex": {
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      "current_release_date": "2026-09-11T16:58:08Z",
      "cve": "CVE-2021-47512",
      "id": "CVE-2021-47512",
      "initial_release_date": "2024-05-28T15:29:53Z",
      "product_status:known_affected": "362",
      "product_status:known_not_affected": "224",
      "product_status:recommended": "404",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-47512",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-47512.json",
      "version": "64"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2024-08-04T05:39:59.825Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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            "references": [
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                "url": "https://git.kernel.org/stable/c/2a51edaf5cc563574878b93d7ef3d5955dda7030"
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                "url": "https://git.kernel.org/stable/c/d86216dfda7c98375f809e26a30bfdaaba21d46e"
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                ],
                "url": "https://git.kernel.org/stable/c/61c2402665f1e10c5742033fce18392e369931d7"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2021-47512",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2024-06-17T17:36:33.443173Z",
                    "version": "2.0.3"
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                  "type": "ssvc"
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            ],
            "providerMetadata": {
              "dateUpdated": "2024-06-17T17:36:34.485Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "net/sched/sch_fq_pie.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "2a51edaf5cc563574878b93d7ef3d5955dda7030",
                  "status": "affected",
                  "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
                  "versionType": "git"
                },
                {
                  "lessThan": "d86216dfda7c98375f809e26a30bfdaaba21d46e",
                  "status": "affected",
                  "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
                  "versionType": "git"
                },
                {
                  "lessThan": "61c2402665f1e10c5742033fce18392e369931d7",
                  "status": "affected",
                  "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
                  "versionType": "git"
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              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "net/sched/sch_fq_pie.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "5.6"
                },
                {
                  "lessThan": "5.6",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
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                {
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                  "status": "unaffected",
                  "version": "5.10.85",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.15.*",
                  "status": "unaffected",
                  "version": "5.15.8",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "5.16",
                  "versionType": "original_commit_for_fix"
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              ]
            }
          ],
          "cpeApplicability": [
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              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.10.85",
                      "versionStartIncluding": "5.6",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.15.8",
                      "versionStartIncluding": "5.6",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.16",
                      "versionStartIncluding": "5.6",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fq_pie: prevent dismantle issue\n\nFor some reason, fq_pie_destroy() did not copy\nworking code from pie_destroy() and other qdiscs,\nthus causing elusive bug.\n\nBefore calling del_timer_sync(\u0026q-\u003eadapt_timer),\nwe need to ensure timer will not rearm itself.\n\nrcu: INFO: rcu_preempt self-detected stall on CPU\nrcu:    0-....: (4416 ticks this GP) idle=60d/1/0x4000000000000000 softirq=10433/10434 fqs=2579\n        (t=10501 jiffies g=13085 q=3989)\nNMI backtrace for cpu 0\nCPU: 0 PID: 13 Comm: ksoftirqd/0 Not tainted 5.16.0-rc4-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\nCall Trace:\n \u003cIRQ\u003e\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106\n nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111\n nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62\n trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]\n rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343\n print_cpu_stall kernel/rcu/tree_stall.h:627 [inline]\n check_cpu_stall kernel/rcu/tree_stall.h:711 [inline]\n rcu_pending kernel/rcu/tree.c:3878 [inline]\n rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597\n update_process_times+0x16d/0x200 kernel/time/timer.c:1785\n tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226\n tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428\n __run_hrtimer kernel/time/hrtimer.c:1685 [inline]\n __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749\n hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811\n local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]\n __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103\n sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097\n \u003c/IRQ\u003e\n \u003cTASK\u003e\n asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638\nRIP: 0010:write_comp_data kernel/kcov.c:221 [inline]\nRIP: 0010:__sanitizer_cov_trace_const_cmp1+0x1d/0x80 kernel/kcov.c:273\nCode: 54 c8 20 48 89 10 c3 66 0f 1f 44 00 00 53 41 89 fb 41 89 f1 bf 03 00 00 00 65 48 8b 0c 25 40 70 02 00 48 89 ce 4c 8b 54 24 08 \u003ce8\u003e 4e f7 ff ff 84 c0 74 51 48 8b 81 88 15 00 00 44 8b 81 84 15 00\nRSP: 0018:ffffc90000d27b28 EFLAGS: 00000246\nRAX: 0000000000000000 RBX: ffff888064bf1bf0 RCX: ffff888011928000\nRDX: ffff888011928000 RSI: ffff888011928000 RDI: 0000000000000003\nRBP: ffff888064bf1c28 R08: 0000000000000000 R09: 0000000000000000\nR10: ffffffff875d8295 R11: 0000000000000000 R12: 0000000000000000\nR13: ffff8880783dd300 R14: 0000000000000000 R15: 0000000000000000\n pie_calculate_probability+0x405/0x7c0 net/sched/sch_pie.c:418\n fq_pie_timer+0x170/0x2a0 net/sched/sch_fq_pie.c:383\n call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421\n expire_timers kernel/time/timer.c:1466 [inline]\n __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734\n __run_timers kernel/time/timer.c:1715 [inline]\n run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747\n __do_softirq+0x29b/0x9c2 kernel/softirq.c:558\n run_ksoftirqd kernel/softirq.c:921 [inline]\n run_ksoftirqd+0x2d/0x60 kernel/softirq.c:913\n smpboot_thread_fn+0x645/0x9c0 kernel/smpboot.c:164\n kthread+0x405/0x4f0 kernel/kthread.c:327\n ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295\n \u003c/TASK\u003e"
            }
          ],
          "metrics": [
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              "cvssV3_1": {
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "scenarios": [
                {
                  "lang": "en",
                  "value": "AV:L - The bug is triggered by creating and destroying an fq_pie qdisc through RTM_NEWQDISC/RTM_DELQDISC rtnetlink (tc), which requires a local netlink socket; no remote peer input reaches fq_pie_destroy or the adapt_timer path.\nAC:L - The attacker controls both sides of the race\u2014arming the self-rearming adapt_timer by installing fq_pie (and can set a short tupdate) then deleting the qdisc to enter fq_pie_destroy\u2014and can retry the create/destroy sequence until the timer runs across the missing tupdate=0 teardown window.\nPR:L - Qdisc configuration is gated only by netlink_net_capable(skb, CAP_NET_ADMIN) against the netns user_ns, so an unprivileged user obtains the needed capability via unshare -Urn and can attach fq_pie on lo; sch_fq_pie is also request_module-autoloadable from that path.\nUI:N - The attacker performs the entire sequence\u2014namespace setup, qdisc create, and qdisc delete\u2014without any action by another user.\nS:U - The timer/UAF and any resulting memory corruption stay inside the host kernel\u2019s own net/sched authority; this is standard local kernel impact with no VM, IOMMU, or sandbox boundary crossed.\nC:H - Without zeroing tupdate before del_timer_sync, the self-rearming timer can still run after teardown while kvfree(q-\u003eflows) has already freed the flow table, yielding a use-after-free read over reclaimable kernel heap that can disclose arbitrary kernel memory.\nI:H - The same post-dismantle UAF on the flows array (and related fq_pie_sched_data state) allows heap reuse and attacker-controlled corruption of kernel objects, matching the net/sched local privilege-escalation pattern for timer-vs-teardown use-after-frees.\nA:H - The observed failure is an RCU self-detected stall / hang in fq_pie_timer, and a use-after-free on freed flows also produces kernel oops/panic; either outcome is a complete availability loss."
                }
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            }
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          "title": "net/sched: fq_pie: prevent dismantle issue",
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      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2021-47512",
        "datePublished": "2024-05-24T15:09:27.356Z",
        "dateReserved": "2024-05-24T15:02:54.824Z",
        "dateUpdated": "2026-08-05T08:48:11.315Z",
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  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.