Vulnerability-Lookup

FKIE_CVE-2025-38193

Vulnerability from fkie_nvd - Published: 2025-07-04 14:15 - Updated: 2026-07-30 06:22

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: net_sched: sch_sfq: reject invalid perturb period Gerrard Tai reported that SFQ perturb_period has no range check yet, and this can be used to trigger a race condition fixed in a separate patch. We want to make sure ctl->perturb_period * HZ will not overflow and is positive. tc qd add dev lo root sfq perturb -10 # negative value : error Error: sch_sfq: invalid perturb period. tc qd add dev lo root sfq perturb 1000000000 # too big : error Error: sch_sfq: invalid perturb period. tc qd add dev lo root sfq perturb 2000000 # acceptable value tc -s -d qd sh dev lo qdisc sfq 8005: root refcnt 2 limit 127p quantum 64Kb depth 127 flows 128 divisor 1024 perturb 2000000sec Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/0357da9149eac621f39e235a135ebf155f01f7c3	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2254d038dab9c194fe6a4b1ce31034f42e91a6e5	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/590b2d7d0beadba2aa576708a05a05f0aae39295	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/7ca52541c05c832d32b112274f81a985101f9ba8	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/956b5aebb349449b38d920d444ca1392d43719d1	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b11a50544af691b787384089b68f740ae20a441b	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/e0936ff56be4e08ad5b60ec26971eae0c40af305	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f9b97d466e6026ccbdda30bb5b71965b67ccbc82	Patch
af854a3a-2127-422b-91ae-364da2661108	https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html	Third Party Advisory
af854a3a-2127-422b-91ae-364da2661108	https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html	Third Party Advisory

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	2.6.12
linux	linux_kernel	2.6.12
linux	linux_kernel	2.6.12
linux	linux_kernel	2.6.12
linux	linux_kernel	2.6.12
linux	linux_kernel	6.16
debian	debian_linux	11.0

JSON

To clipboard

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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: sch_sfq: reject invalid perturb period\n\nGerrard Tai reported that SFQ perturb_period has no range check yet,\nand this can be used to trigger a race condition fixed in a separate patch.\n\nWe want to make sure ctl-\u003eperturb_period * HZ will not overflow\nand is positive.\n\n\ntc qd add dev lo root sfq perturb -10   # negative value : error\nError: sch_sfq: invalid perturb period.\n\ntc qd add dev lo root sfq perturb 1000000000 # too big : error\nError: sch_sfq: invalid perturb period.\n\ntc qd add dev lo root sfq perturb 2000000 # acceptable value\ntc -s -d qd sh dev lo\nqdisc sfq 8005: root refcnt 2 limit 127p quantum 64Kb depth 127 flows 128 divisor 1024 perturb 2000000sec\n Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)\n backlog 0b 0p requeues 0"
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net_sched: sch_sfq: rechaza un per\u00edodo de perturbaci\u00f3n no v\u00e1lido. Gerrard Tai inform\u00f3 que SFQ perturb_period a\u00fan no tiene comprobaci\u00f3n de rango, lo que puede usarse para activar una condici\u00f3n de ejecuci\u00f3n corregida en un parche independiente. Queremos asegurarnos de que ctl-\u0026gt;perturb_period * HZ no se desborde y sea positivo. tc qd add dev lo root sfq perturb -10 # valor negativo: error. Error: sch_sfq: per\u00edodo de perturbaci\u00f3n no v\u00e1lido. tc qd add dev lo root sfq perturb 100000000 # demasiado grande: error. Error: sch_sfq: per\u00edodo de perturbaci\u00f3n no v\u00e1lido. tc qd add dev lo root sfq perturb 2000000 # valor aceptable tc -s -d qd sh dev lo qdisc sfq 8005: root refcnt 2 limit 127p quantum 64Kb Depth 127 flows 128 divisor 1024 perturb 2000000sec Enviados 0 bytes 0 paquete (eliminados 0, sobrepasa los l\u00edmites 0, vuelve a poner en cola 0) backlog 0b 0p vuelve a poner en cola 0"
    }
  ],
  "id": "CVE-2025-38193",
  "lastModified": "2026-07-30T06:22:59.313",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      },
      {
        "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": "2025-07-04T14:15:26.403",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
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    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    },
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    },
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    },
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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    },
    {
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      "tags": [
        "Patch"
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    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "tags": [
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      "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-190"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2025-38193 (GCVE-0-2025-38193)

Vulnerability from cvelistv5 – Published: 2025-07-04 13:37 – Updated: 2026-08-05 12:00

Title

net_sched: sch_sfq: reject invalid perturb period

Summary

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root Scorecard

References

10 references

URL	Tags
https://git.kernel.org/stable/c/e0936ff56be4e08ad…
https://git.kernel.org/stable/c/2254d038dab9c194f…
https://git.kernel.org/stable/c/956b5aebb349449b3…
https://git.kernel.org/stable/c/b11a50544af691b78…
https://git.kernel.org/stable/c/0357da9149eac621f…
https://git.kernel.org/stable/c/f9b97d466e6026ccb…
https://git.kernel.org/stable/c/590b2d7d0beadba2a…
https://git.kernel.org/stable/c/7ca52541c05c832d3…
https://lists.debian.org/debian-lts-announce/2025…
https://lists.debian.org/debian-lts-announce/2025…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < e0936ff56be4e08ad5b60ec26971eae0c40af305 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 2254d038dab9c194fe6a4b1ce31034f42e91a6e5 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 956b5aebb349449b38d920d444ca1392d43719d1 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < b11a50544af691b787384089b68f740ae20a441b (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 0357da9149eac621f39e235a135ebf155f01f7c3 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < f9b97d466e6026ccbdda30bb5b71965b67ccbc82 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 590b2d7d0beadba2aa576708a05a05f0aae39295 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 7ca52541c05c832d32b112274f81a985101f9ba8 (git)
Linux	Linux	Affected: 2.6.12 Unaffected: 0 , < 2.6.12 (semver) Unaffected: 5.4.297 , ≤ 5.4.* (semver) Unaffected: 5.10.240 , ≤ 5.10.* (semver) Unaffected: 5.15.186 , ≤ 5.15.* (semver) Unaffected: 6.1.142 , ≤ 6.1.* (semver) Unaffected: 6.6.95 , ≤ 6.6.* (semver) Unaffected: 6.12.35 , ≤ 6.12.* (semver) Unaffected: 6.15.4 , ≤ 6.15.* (semver) Unaffected: 6.16 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
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        "providerMetadata": {
          "dateUpdated": "2025-11-03T17:35:17.196Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
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            "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
          },
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_sfq.c"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e0936ff56be4e08ad5b60ec26971eae0c40af305",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "2254d038dab9c194fe6a4b1ce31034f42e91a6e5",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "956b5aebb349449b38d920d444ca1392d43719d1",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "b11a50544af691b787384089b68f740ae20a441b",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "0357da9149eac621f39e235a135ebf155f01f7c3",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "f9b97d466e6026ccbdda30bb5b71965b67ccbc82",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "590b2d7d0beadba2aa576708a05a05f0aae39295",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "7ca52541c05c832d32b112274f81a985101f9ba8",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_sfq.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.12"
            },
            {
              "lessThan": "2.6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.297",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.240",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.186",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.142",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.95",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.35",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.15.*",
              "status": "unaffected",
              "version": "6.15.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.16",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.297",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.240",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.186",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.142",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.95",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.35",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.15.4",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: sch_sfq: reject invalid perturb period\n\nGerrard Tai reported that SFQ perturb_period has no range check yet,\nand this can be used to trigger a race condition fixed in a separate patch.\n\nWe want to make sure ctl-\u003eperturb_period * HZ will not overflow\nand is positive.\n\n\ntc qd add dev lo root sfq perturb -10   # negative value : error\nError: sch_sfq: invalid perturb period.\n\ntc qd add dev lo root sfq perturb 1000000000 # too big : error\nError: sch_sfq: invalid perturb period.\n\ntc qd add dev lo root sfq perturb 2000000 # acceptable value\ntc -s -d qd sh dev lo\nqdisc sfq 8005: root refcnt 2 limit 127p quantum 64Kb depth 127 flows 128 divisor 1024 perturb 2000000sec\n Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)\n backlog 0b 0p requeues 0"
        }
      ],
      "metrics": [
        {
          "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 attacker-controlled `perturb_period` arrives via an RTM_NEWQDISC netlink message on an AF_NETLINK socket (tc qdisc add/change), which requires local system access. No remote peer or packet data can influence this value.\nAC:L - A single deterministic command (`tc qdisc add dev lo root sfq perturb -10`, or a value that overflows `* HZ`) sets the malicious period every time, with no reliance on conditions outside the attacker\u0027s control; for the downstream qdisc race, this bug is itself the mechanism that makes the timing attacker-controlled and the race reliably winnable.\nPR:L - The path is gated only by `netlink_net_capable(skb, CAP_NET_ADMIN)`, evaluated against the netns owner\u0027s user namespace, so any unprivileged user obtains it with `unshare -Urn` and then configures SFQ on lo/veth. `sch_sfq` is loaded on demand via module alias, so no real root in the initial namespace is required.\nUI:N - The attacker performs the entire sequence \u2014 create the namespace, add the SFQ qdisc with the invalid period, and drive the parent qdisc change \u2014 with no action by any other user.\nS:U - The corrupted state (SFQ timer state, parent qdisc qlen/backlog accounting, and resulting freed qdisc objects) all lives within the kernel\u0027s own security authority; this is standard kernel-local escalation, not a VM, IOMMU, or hypervisor boundary crossing.\nC:H - By making the SFQ perturb timer fire at an attacker-chosen instant, this bug enables the parent-qdisc qlen/backlog underflow that yields a use-after-free of qdisc objects, giving an attacker-controllable read primitive over reclaimed kernel memory and disclosure of arbitrary kernel data.\nI:H - The same underflow-driven use-after-free permits heap spraying over the freed qdisc allocation and attacker-controlled writes into kernel structures (including function pointers in Qdisc_ops paths), which is the documented route to full privilege escalation for this class of net/sched bug.\nA:H - A negative period makes `mod_timer(jiffies + period)` expire in the past, so `sfq_perturbation()` re-arms and re-fires every tick forever, holding the root qdisc lock while rehashing every queued packet across up to 65408 flows \u2014 a permanent softirq livelock that stalls the device\u0027s transmit path, and the resulting UAF crashes the kernel outright."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:00:18.140Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e0936ff56be4e08ad5b60ec26971eae0c40af305"
        },
        {
          "url": "https://git.kernel.org/stable/c/2254d038dab9c194fe6a4b1ce31034f42e91a6e5"
        },
        {
          "url": "https://git.kernel.org/stable/c/956b5aebb349449b38d920d444ca1392d43719d1"
        },
        {
          "url": "https://git.kernel.org/stable/c/b11a50544af691b787384089b68f740ae20a441b"
        },
        {
          "url": "https://git.kernel.org/stable/c/0357da9149eac621f39e235a135ebf155f01f7c3"
        },
        {
          "url": "https://git.kernel.org/stable/c/f9b97d466e6026ccbdda30bb5b71965b67ccbc82"
        },
        {
          "url": "https://git.kernel.org/stable/c/590b2d7d0beadba2aa576708a05a05f0aae39295"
        },
        {
          "url": "https://git.kernel.org/stable/c/7ca52541c05c832d32b112274f81a985101f9ba8"
        }
      ],
      "title": "net_sched: sch_sfq: reject invalid perturb period",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-38193",
    "datePublished": "2025-07-04T13:37:17.285Z",
    "dateReserved": "2025-04-16T04:51:23.993Z",
    "dateUpdated": "2026-08-05T12:00:18.140Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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FKIE_CVE-2025-38193

CVE-2025-38193 (GCVE-0-2025-38193)

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