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CVE-2025-40257 (GCVE-0-2025-40257)

Vulnerability from cvelistv5 – Published: 2025-12-04 16:08 – Updated: 2026-08-05 12:08
VLAI
Title
mptcp: fix a race in mptcp_pm_del_add_timer()
Summary
In the Linux kernel, the following vulnerability has been resolved: mptcp: fix a race in mptcp_pm_del_add_timer() mptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry->add_timer) while another might have free entry already, as reported by syzbot. Add RCU protection to fix this issue. Also change confusing add_timer variable with stop_timer boolean. syzbot report: BUG: KASAN: slab-use-after-free in __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616 Read of size 4 at addr ffff8880311e4150 by task kworker/1:1/44 CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events mptcp_worker Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x240 mm/kasan/report.c:482 kasan_report+0x118/0x150 mm/kasan/report.c:595 __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616 sk_stop_timer_sync+0x1b/0x90 net/core/sock.c:3631 mptcp_pm_del_add_timer+0x283/0x310 net/mptcp/pm.c:362 mptcp_incoming_options+0x1357/0x1f60 net/mptcp/options.c:1174 tcp_data_queue+0xca/0x6450 net/ipv4/tcp_input.c:5361 tcp_rcv_established+0x1335/0x2670 net/ipv4/tcp_input.c:6441 tcp_v4_do_rcv+0x98b/0xbf0 net/ipv4/tcp_ipv4.c:1931 tcp_v4_rcv+0x252a/0x2dc0 net/ipv4/tcp_ipv4.c:2374 ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:239 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6079 [inline] __netif_receive_skb+0x143/0x380 net/core/dev.c:6192 process_backlog+0x31e/0x900 net/core/dev.c:6544 __napi_poll+0xb6/0x540 net/core/dev.c:7594 napi_poll net/core/dev.c:7657 [inline] net_rx_action+0x5f7/0xda0 net/core/dev.c:7784 handle_softirqs+0x22f/0x710 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] __local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302 mptcp_pm_send_ack net/mptcp/pm.c:210 [inline] mptcp_pm_addr_send_ack+0x41f/0x500 net/mptcp/pm.c:-1 mptcp_pm_worker+0x174/0x320 net/mptcp/pm.c:1002 mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> Allocated by task 44: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:400 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417 kasan_kmalloc include/linux/kasan.h:262 [inline] __kmalloc_cache_noprof+0x1ef/0x6c0 mm/slub.c:5748 kmalloc_noprof include/linux/slab.h:957 [inline] mptcp_pm_alloc_anno_list+0x104/0x460 net/mptcp/pm.c:385 mptcp_pm_create_subflow_or_signal_addr+0xf9d/0x1360 net/mptcp/pm_kernel.c:355 mptcp_pm_nl_fully_established net/mptcp/pm_kernel.c:409 [inline] __mptcp_pm_kernel_worker+0x417/0x1ef0 net/mptcp/pm_kernel.c:1529 mptcp_pm_worker+0x1ee/0x320 net/mptcp/pm.c:1008 mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Freed by task 6630: kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object m ---truncated---
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 00cfd77b9063dcdf3628a7087faba60de85a9cc8 , < 9be29f8e7ce4e147e56caac2c3a0ce3573cf9c17 (git)
Affected: 00cfd77b9063dcdf3628a7087faba60de85a9cc8 , < e2d1ad207174a7cd7903dd27a00db4b2dfa6c64b (git)
Affected: 00cfd77b9063dcdf3628a7087faba60de85a9cc8 , < 385ddc0f008f24d1e7d03be998b3a98a37bd29ff (git)
Affected: 00cfd77b9063dcdf3628a7087faba60de85a9cc8 , < c602cc344b4b8d41515fec3ffa98457ac963ee12 (git)
Affected: 00cfd77b9063dcdf3628a7087faba60de85a9cc8 , < 6d3275d4ca62e2c02e1b7e8cd32db59df91c14b7 (git)
Affected: 00cfd77b9063dcdf3628a7087faba60de85a9cc8 , < bbbd75346c8e6490b19c2ba90f38ea66ccf352b2 (git)
Affected: 00cfd77b9063dcdf3628a7087faba60de85a9cc8 , < 426358d9be7ce3518966422f87b96f1bad27295f (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.10
Unaffected: 0 , < 5.10 (semver)
Unaffected: 5.10.247 , ≤ 5.10.* (semver)
Unaffected: 5.15.197 , ≤ 5.15.* (semver)
Unaffected: 6.1.159 , ≤ 6.1.* (semver)
Unaffected: 6.6.118 , ≤ 6.6.* (semver)
Unaffected: 6.12.60 , ≤ 6.12.* (semver)
Unaffected: 6.17.10 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Siemens RUGGEDCOM RST2428P Affected: 0 , < V4.0 (custom)
guessed Create a notification for this product.
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix a race in mptcp_pm_del_add_timer()\n\nmptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, \u0026entry-\u003eadd_timer)\nwhile another might have free entry already, as reported by syzbot.\n\nAdd RCU protection to fix this issue.\n\nAlso change confusing add_timer variable with stop_timer boolean.\n\nsyzbot report:\n\nBUG: KASAN: slab-use-after-free in __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616\nRead of size 4 at addr ffff8880311e4150 by task kworker/1:1/44\n\nCPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025\nWorkqueue: events mptcp_worker\nCall Trace:\n \u003cTASK\u003e\n  dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120\n  print_address_description mm/kasan/report.c:378 [inline]\n  print_report+0xca/0x240 mm/kasan/report.c:482\n  kasan_report+0x118/0x150 mm/kasan/report.c:595\n  __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616\n  sk_stop_timer_sync+0x1b/0x90 net/core/sock.c:3631\n  mptcp_pm_del_add_timer+0x283/0x310 net/mptcp/pm.c:362\n  mptcp_incoming_options+0x1357/0x1f60 net/mptcp/options.c:1174\n  tcp_data_queue+0xca/0x6450 net/ipv4/tcp_input.c:5361\n  tcp_rcv_established+0x1335/0x2670 net/ipv4/tcp_input.c:6441\n  tcp_v4_do_rcv+0x98b/0xbf0 net/ipv4/tcp_ipv4.c:1931\n  tcp_v4_rcv+0x252a/0x2dc0 net/ipv4/tcp_ipv4.c:2374\n  ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:205\n  ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:239\n  NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318\n  NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318\n  __netif_receive_skb_one_core net/core/dev.c:6079 [inline]\n  __netif_receive_skb+0x143/0x380 net/core/dev.c:6192\n  process_backlog+0x31e/0x900 net/core/dev.c:6544\n  __napi_poll+0xb6/0x540 net/core/dev.c:7594\n  napi_poll net/core/dev.c:7657 [inline]\n  net_rx_action+0x5f7/0xda0 net/core/dev.c:7784\n  handle_softirqs+0x22f/0x710 kernel/softirq.c:622\n  __do_softirq kernel/softirq.c:656 [inline]\n  __local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302\n  mptcp_pm_send_ack net/mptcp/pm.c:210 [inline]\n mptcp_pm_addr_send_ack+0x41f/0x500 net/mptcp/pm.c:-1\n  mptcp_pm_worker+0x174/0x320 net/mptcp/pm.c:1002\n  mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762\n  process_one_work kernel/workqueue.c:3263 [inline]\n  process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346\n  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427\n  kthread+0x711/0x8a0 kernel/kthread.c:463\n  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158\n  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n \u003c/TASK\u003e\n\nAllocated by task 44:\n  kasan_save_stack mm/kasan/common.c:56 [inline]\n  kasan_save_track+0x3e/0x80 mm/kasan/common.c:77\n  poison_kmalloc_redzone mm/kasan/common.c:400 [inline]\n  __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417\n  kasan_kmalloc include/linux/kasan.h:262 [inline]\n  __kmalloc_cache_noprof+0x1ef/0x6c0 mm/slub.c:5748\n  kmalloc_noprof include/linux/slab.h:957 [inline]\n  mptcp_pm_alloc_anno_list+0x104/0x460 net/mptcp/pm.c:385\n  mptcp_pm_create_subflow_or_signal_addr+0xf9d/0x1360 net/mptcp/pm_kernel.c:355\n  mptcp_pm_nl_fully_established net/mptcp/pm_kernel.c:409 [inline]\n  __mptcp_pm_kernel_worker+0x417/0x1ef0 net/mptcp/pm_kernel.c:1529\n  mptcp_pm_worker+0x1ee/0x320 net/mptcp/pm.c:1008\n  mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762\n  process_one_work kernel/workqueue.c:3263 [inline]\n  process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346\n  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427\n  kthread+0x711/0x8a0 kernel/kthread.c:463\n  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158\n  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n\nFreed by task 6630:\n  kasan_save_stack mm/kasan/common.c:56 [inline]\n  kasan_save_track+0x3e/0x80 mm/kasan/common.c:77\n  __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587\n  kasan_save_free_info mm/kasan/kasan.h:406 [inline]\n  poison_slab_object m\n---truncated---"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The use-after-free is dereferenced inside `mptcp_incoming_options()` while parsing an MPTCP ADD_ADDR echo option received from a remote peer (`tcp_v4_rcv \u2192 tcp_rcv_established \u2192 tcp_data_queue \u2192 mptcp_incoming_options \u2192 mptcp_pm_del_add_timer`), as shown verbatim in the syzbot stack. Any remote MPTCP peer of an internet-facing MPTCP-enabled server reaches this code with ordinary TCP packets.\nAC:L - The attacker controls both sides of the race \u2014 the ADD_ADDR echo can be emitted at will and repeatedly to keep a thread parked in the unlocked window, while the freeing side (`FLUSH_ADDRS`/`DEL_ADDR`/userspace-PM `REMOVE`) is either driven by the PM daemon reacting to the attacker\u0027s own MPTCP address events or issued directly by a local attacker looping netlink calls. Both `mptcp_pm_del_add_timer()` callers are trivially invokable in a tight loop, so the window is hit reliably.\nPR:N - A remote MPTCP peer needs no credentials or privileges on the target \u2014 only an established MPTCP connection, whose keys are what `add_addr_hmac_valid()` checks. Even the netlink half of the race is only `GENL_UNS_ADMIN_PERM`, i.e. CAP_NET_ADMIN reachable by an unprivileged user via `unshare -Urn`, so no real privilege is required anywhere on the path.\nUI:N - Exploitation happens entirely in the kernel\u0027s TCP receive path and the MPTCP path-manager worker; no victim action, mount, or file open is needed.\nS:U - The corruption is confined to kernel slab memory and the compromised component is the kernel itself, so there is no crossing into a different security authority.\nC:H - The freed `mptcp_pm_add_entry` lives in a sprayable general kmalloc cache; after reclaim, `__timer_delete_sync()` reads attacker-groomed memory and a fired `mptcp_pm_add_timer()` re-announces `entry-\u003eaddr` from the reclaimed object, leaking kernel heap contents onto the wire and yielding an arbitrary-read primitive via the confused `entry-\u003esock` pointer.\nI:H - `__timer_delete_sync()` writes into the freed timer during detach, and a timer firing out of a reallocated object drives `sk_reset_timer()`/`__sock_put()` on a fully attacker-controlled `entry-\u003esock` pointer \u2014 a wild-pointer write and refcount decrement suitable for heap grooming into control-flow hijack.\nA:H - KASAN confirms a slab-use-after-free in `__timer_delete_sync()`; unmitigated this reliably corrupts timer-base list state and oopses or panics the kernel, and the race can be re-triggered repeatedly from the network for a persistent denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:08:57.025Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9be29f8e7ce4e147e56caac2c3a0ce3573cf9c17"
        },
        {
          "url": "https://git.kernel.org/stable/c/e2d1ad207174a7cd7903dd27a00db4b2dfa6c64b"
        },
        {
          "url": "https://git.kernel.org/stable/c/385ddc0f008f24d1e7d03be998b3a98a37bd29ff"
        },
        {
          "url": "https://git.kernel.org/stable/c/c602cc344b4b8d41515fec3ffa98457ac963ee12"
        },
        {
          "url": "https://git.kernel.org/stable/c/6d3275d4ca62e2c02e1b7e8cd32db59df91c14b7"
        },
        {
          "url": "https://git.kernel.org/stable/c/bbbd75346c8e6490b19c2ba90f38ea66ccf352b2"
        },
        {
          "url": "https://git.kernel.org/stable/c/426358d9be7ce3518966422f87b96f1bad27295f"
        }
      ],
      "title": "mptcp: fix a race in mptcp_pm_del_add_timer()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40257",
    "datePublished": "2025-12-04T16:08:18.433Z",
    "dateReserved": "2025-04-16T07:20:57.182Z",
    "dateUpdated": "2026-08-05T12:08:57.025Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-40257",
      "date": "2026-09-20",
      "epss": "0.00464",
      "percentile": "0.3944"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/mptcp/pm.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "9be29f8e7ce4e147e56caac2c3a0ce3573cf9c17",
                    "status": "affected",
                    "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "e2d1ad207174a7cd7903dd27a00db4b2dfa6c64b",
                    "status": "affected",
                    "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "385ddc0f008f24d1e7d03be998b3a98a37bd29ff",
                    "status": "affected",
                    "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "c602cc344b4b8d41515fec3ffa98457ac963ee12",
                    "status": "affected",
                    "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "6d3275d4ca62e2c02e1b7e8cd32db59df91c14b7",
                    "status": "affected",
                    "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "bbbd75346c8e6490b19c2ba90f38ea66ccf352b2",
                    "status": "affected",
                    "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "426358d9be7ce3518966422f87b96f1bad27295f",
                    "status": "affected",
                    "version": "00cfd77b9063dcdf3628a7087faba60de85a9cc8",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "net/mptcp/pm.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "5.10"
                  },
                  {
                    "lessThan": "5.10",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.10.*",
                    "status": "unaffected",
                    "version": "5.10.247",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.15.*",
                    "status": "unaffected",
                    "version": "5.15.197",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.1.*",
                    "status": "unaffected",
                    "version": "6.1.159",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.118",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.60",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.17.*",
                    "status": "unaffected",
                    "version": "6.17.10",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "6.18",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          },
          {
            "affectedData": [
              {
                "defaultStatus": "unknown",
                "product": "RUGGEDCOM RST2428P",
                "vendor": "Siemens",
                "versions": [
                  {
                    "lessThan": "V4.0",
                    "status": "affected",
                    "version": "0",
                    "versionType": "custom"
                  }
                ]
              }
            ],
            "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix a race in mptcp_pm_del_add_timer()\n\nmptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, \u0026entry-\u003eadd_timer)\nwhile another might have free entry already, as reported by syzbot.\n\nAdd RCU protection to fix this issue.\n\nAlso change confusing add_timer variable with stop_timer boolean.\n\nsyzbot report:\n\nBUG: KASAN: slab-use-after-free in __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616\nRead of size 4 at addr ffff8880311e4150 by task kworker/1:1/44\n\nCPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025\nWorkqueue: events mptcp_worker\nCall Trace:\n \u003cTASK\u003e\n  dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120\n  print_address_description mm/kasan/report.c:378 [inline]\n  print_report+0xca/0x240 mm/kasan/report.c:482\n  kasan_report+0x118/0x150 mm/kasan/report.c:595\n  __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616\n  sk_stop_timer_sync+0x1b/0x90 net/core/sock.c:3631\n  mptcp_pm_del_add_timer+0x283/0x310 net/mptcp/pm.c:362\n  mptcp_incoming_options+0x1357/0x1f60 net/mptcp/options.c:1174\n  tcp_data_queue+0xca/0x6450 net/ipv4/tcp_input.c:5361\n  tcp_rcv_established+0x1335/0x2670 net/ipv4/tcp_input.c:6441\n  tcp_v4_do_rcv+0x98b/0xbf0 net/ipv4/tcp_ipv4.c:1931\n  tcp_v4_rcv+0x252a/0x2dc0 net/ipv4/tcp_ipv4.c:2374\n  ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:205\n  ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:239\n  NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318\n  NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318\n  __netif_receive_skb_one_core net/core/dev.c:6079 [inline]\n  __netif_receive_skb+0x143/0x380 net/core/dev.c:6192\n  process_backlog+0x31e/0x900 net/core/dev.c:6544\n  __napi_poll+0xb6/0x540 net/core/dev.c:7594\n  napi_poll net/core/dev.c:7657 [inline]\n  net_rx_action+0x5f7/0xda0 net/core/dev.c:7784\n  handle_softirqs+0x22f/0x710 kernel/softirq.c:622\n  __do_softirq kernel/softirq.c:656 [inline]\n  __local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302\n  mptcp_pm_send_ack net/mptcp/pm.c:210 [inline]\n mptcp_pm_addr_send_ack+0x41f/0x500 net/mptcp/pm.c:-1\n  mptcp_pm_worker+0x174/0x320 net/mptcp/pm.c:1002\n  mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762\n  process_one_work kernel/workqueue.c:3263 [inline]\n  process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346\n  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427\n  kthread+0x711/0x8a0 kernel/kthread.c:463\n  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158\n  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n \u003c/TASK\u003e\n\nAllocated by task 44:\n  kasan_save_stack mm/kasan/common.c:56 [inline]\n  kasan_save_track+0x3e/0x80 mm/kasan/common.c:77\n  poison_kmalloc_redzone mm/kasan/common.c:400 [inline]\n  __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417\n  kasan_kmalloc include/linux/kasan.h:262 [inline]\n  __kmalloc_cache_noprof+0x1ef/0x6c0 mm/slub.c:5748\n  kmalloc_noprof include/linux/slab.h:957 [inline]\n  mptcp_pm_alloc_anno_list+0x104/0x460 net/mptcp/pm.c:385\n  mptcp_pm_create_subflow_or_signal_addr+0xf9d/0x1360 net/mptcp/pm_kernel.c:355\n  mptcp_pm_nl_fully_established net/mptcp/pm_kernel.c:409 [inline]\n  __mptcp_pm_kernel_worker+0x417/0x1ef0 net/mptcp/pm_kernel.c:1529\n  mptcp_pm_worker+0x1ee/0x320 net/mptcp/pm.c:1008\n  mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762\n  process_one_work kernel/workqueue.c:3263 [inline]\n  process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346\n  worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427\n  kthread+0x711/0x8a0 kernel/kthread.c:463\n  ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158\n  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n\nFreed by task 6630:\n  kasan_save_stack mm/kasan/common.c:56 [inline]\n  kasan_save_track+0x3e/0x80 mm/kasan/common.c:77\n  __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587\n  kasan_save_free_info mm/kasan/kasan.h:406 [inline]\n  poison_slab_object m\n---truncated---"
          }
        ],
        "id": "CVE-2025-40257",
        "lastModified": "2026-07-30T06:24:22.993",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 9.8,
                "baseSeverity": "CRITICAL",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2025-12-04T16:16:19.503",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/385ddc0f008f24d1e7d03be998b3a98a37bd29ff"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/426358d9be7ce3518966422f87b96f1bad27295f"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/6d3275d4ca62e2c02e1b7e8cd32db59df91c14b7"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/9be29f8e7ce4e147e56caac2c3a0ce3573cf9c17"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/bbbd75346c8e6490b19c2ba90f38ea66ccf352b2"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/c602cc344b4b8d41515fec3ffa98457ac963ee12"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/e2d1ad207174a7cd7903dd27a00db4b2dfa6c64b"
          },
          {
            "source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
            "url": "https://cert-portal.siemens.com/productcert/html/ssa-253495.html"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Deferred"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T18:58:40+00:00",
      "cve": "CVE-2025-40257",
      "id": "CVE-2025-40257",
      "initial_release_date": "2025-12-04T00:00:00+00:00",
      "product_status:fixed": "309",
      "product_status:known_affected": "156",
      "product_status:known_not_affected": "42",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel MPTCP: Privilege escalation or denial of service via use-after-free in timer handling",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-40257.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-19T02:05:54Z",
      "cve": "CVE-2025-40257",
      "id": "CVE-2025-40257",
      "initial_release_date": "2025-12-05T00:25:22Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "399",
      "product_status:known_not_affected": "260",
      "product_status:recommended": "580",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-40257",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-40257.json",
      "version": "50"
    }
  }
}



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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.


Detection rules are retrieved from Rulezet.


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.