CVE-2025-68250 (GCVE-0-2025-68250)

Vulnerability from cvelistv5 – Published: 2025-12-16 14:32 – Updated: 2026-08-05 12:10
VLAI
Title
hung_task: fix warnings caused by unaligned lock pointers
Summary
In the Linux kernel, the following vulnerability has been resolved: hung_task: fix warnings caused by unaligned lock pointers The blocker tracking mechanism assumes that lock pointers are at least 4-byte aligned to use their lower bits for type encoding. However, as reported by Eero Tamminen, some architectures like m68k only guarantee 2-byte alignment of 32-bit values. This breaks the assumption and causes two related WARN_ON_ONCE checks to trigger. To fix this, the runtime checks are adjusted to silently ignore any lock that is not 4-byte aligned, effectively disabling the feature in such cases and avoiding the related warnings. Thanks to Geert Uytterhoeven for bisecting!
Severity
8.2 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6664 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: e711faaafbe54a884f33b53472434063d342f6d4 , < c0e2dcbe54cb15ecdf9d8f4501c6720423243888 (git)
Affected: e711faaafbe54a884f33b53472434063d342f6d4 , < c97513cddcfc235f2522617980838e500af21d01 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.17.6 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/hung_task.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c0e2dcbe54cb15ecdf9d8f4501c6720423243888",
              "status": "affected",
              "version": "e711faaafbe54a884f33b53472434063d342f6d4",
              "versionType": "git"
            },
            {
              "lessThan": "c97513cddcfc235f2522617980838e500af21d01",
              "status": "affected",
              "version": "e711faaafbe54a884f33b53472434063d342f6d4",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/linux/hung_task.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17.6",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhung_task: fix warnings caused by unaligned lock pointers\n\nThe blocker tracking mechanism assumes that lock pointers are at least\n4-byte aligned to use their lower bits for type encoding.\n\nHowever, as reported by Eero Tamminen, some architectures like m68k\nonly guarantee 2-byte alignment of 32-bit values. This breaks the\nassumption and causes two related WARN_ON_ONCE checks to trigger.\n\nTo fix this, the runtime checks are adjusted to silently ignore any lock\nthat is not 4-byte aligned, effectively disabling the feature in such\ncases and avoiding the related warnings.\n\nThanks to Geert Uytterhoeven for bisecting!"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.2,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - On an affected m68k system running ksmbd, remote SMB2 IPC-pipe requests can contend on the unaligned session RPC rwsem and reach the vulnerable blocker tracking code over TCP/445.\nAC:L - The client can deterministically trigger the contemporaneous recursive-lock path or control concurrent requests against one session, so exploitation requires no uncontrollable race or memory-layout manipulation.\nPR:N - KSMBD permits passwordless guest sessions and allows restricted guest RPC operations, making the path reachable without credentials in a reasonable guest-enabled deployment.\nUI:N - Once the service is configured, attacker-supplied SMB requests trigger the vulnerable path without victim action.\nS:U - The warning, information exposure, and possible panic affect the same kernel and host security authority as the vulnerable code.\nC:L - The warning dumps kernel addresses and up to 48 raw m68k stack words, providing a bounded information disclosure where the kernel log or console is accessible.\nI:N - The rejected unaligned pointer is never stored or dereferenced, and the bug causes no memory corruption or attacker-controlled data modification.\nA:H - The warning immediately panics the kernel when panic_on_warn is enabled or the warning limit is reached, causing complete host unavailability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:10:27.999Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c0e2dcbe54cb15ecdf9d8f4501c6720423243888"
        },
        {
          "url": "https://git.kernel.org/stable/c/c97513cddcfc235f2522617980838e500af21d01"
        }
      ],
      "title": "hung_task: fix warnings caused by unaligned lock pointers",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68250",
    "datePublished": "2025-12-16T14:32:17.173Z",
    "dateReserved": "2025-12-16T13:41:40.266Z",
    "dateUpdated": "2026-08-05T12:10:27.999Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-68250",
      "date": "2026-10-17",
      "epss": "0.00307",
      "percentile": "0.21991"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "include/linux/hung_task.h"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "c0e2dcbe54cb15ecdf9d8f4501c6720423243888",
                    "status": "affected",
                    "version": "e711faaafbe54a884f33b53472434063d342f6d4",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "c97513cddcfc235f2522617980838e500af21d01",
                    "status": "affected",
                    "version": "e711faaafbe54a884f33b53472434063d342f6d4",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "include/linux/hung_task.h"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "6.16"
                  },
                  {
                    "lessThan": "6.16",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.17.*",
                    "status": "unaffected",
                    "version": "6.17.6",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "6.18",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nhung_task: fix warnings caused by unaligned lock pointers\n\nThe blocker tracking mechanism assumes that lock pointers are at least\n4-byte aligned to use their lower bits for type encoding.\n\nHowever, as reported by Eero Tamminen, some architectures like m68k\nonly guarantee 2-byte alignment of 32-bit values. This breaks the\nassumption and causes two related WARN_ON_ONCE checks to trigger.\n\nTo fix this, the runtime checks are adjusted to silently ignore any lock\nthat is not 4-byte aligned, effectively disabling the feature in such\ncases and avoiding the related warnings.\n\nThanks to Geert Uytterhoeven for bisecting!"
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nhung_task: corrige advertencias causadas por punteros de bloqueo no alineados\n\nEl mecanismo de seguimiento de bloqueadores asume que los punteros de bloqueo est\u00e1n alineados a al menos 4 bytes para usar sus bits inferiores para la codificaci\u00f3n de tipos.\n\nSin embargo, como inform\u00f3 Eero Tamminen, algunas arquitecturas como m68k solo garantizan una alineaci\u00f3n de 2 bytes de valores de 32 bits. Esto rompe la suposici\u00f3n y causa que se activen dos comprobaciones WARN_ON_ONCE relacionadas.\n\nPara solucionar esto, las comprobaciones en tiempo de ejecuci\u00f3n se ajustan para ignorar silenciosamente cualquier bloqueo que no est\u00e9 alineado a 4 bytes, deshabilitando efectivamente la caracter\u00edstica en tales casos y evitando las advertencias relacionadas.\n\n\u00a1Gracias a Geert Uytterhoeven por el bisect!"
          }
        ],
        "id": "CVE-2025-68250",
        "lastModified": "2026-10-14T13:10:00.187",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 8.2,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "LOW",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 4.2,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2025-12-16T15:15:54.307",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/c0e2dcbe54cb15ecdf9d8f4501c6720423243888"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/c97513cddcfc235f2522617980838e500af21d01"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Deferred"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-10-16T23:24:27+00:00",
      "cve": "CVE-2025-68250",
      "id": "CVE-2025-68250",
      "initial_release_date": "2025-12-16T00:00:00+00:00",
      "product_status:known_affected": "14",
      "product_status:known_not_affected": "261",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: hung_task: fix warnings caused by unaligned lock pointers",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-68250.json",
      "version": "3"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

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

Author Source Type Date Other

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    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.