Vulnerability-Lookup

CVE-2026-31641 (GCVE-0-2026-31641)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:44 – Updated: 2026-04-24 14:44

Title

rxrpc: Fix RxGK token loading to check bounds

Summary

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix RxGK token loading to check bounds rxrpc_preparse_xdr_yfs_rxgk() reads the raw key length and ticket length from the XDR token as u32 values and passes each through round_up(x, 4) before using the rounded value for validation and allocation. When the raw length is >= 0xfffffffd, round_up() wraps to 0, so the bounds check and kzalloc both use 0 while the subsequent memcpy still copies the original ~4 GiB value, producing a heap buffer overflow reachable from an unprivileged add_key() call. Fix this by: (1) Rejecting raw key lengths above AFSTOKEN_GK_KEY_MAX and raw ticket lengths above AFSTOKEN_GK_TOKEN_MAX before rounding, consistent with the caps that the RxKAD path already enforces via AFSTOKEN_RK_TIX_MAX. (2) Sizing the flexible-array allocation from the validated raw key length via struct_size_t() instead of the rounded value. (3) Caching the raw lengths so that the later field assignments and memcpy calls do not re-read from the token, eliminating a class of TOCTOU re-parse. The control path (valid token with lengths within bounds) is unaffected.

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/3e04596cba8a86cbf…
	https://git.kernel.org/stable/c/49875b360c2b83a3c…
	https://git.kernel.org/stable/c/d179a868dd755b0cf…

Impacted products

Vendor

Product

Version

Linux

Affected: 0ca100ff4df64f5d0f6c1dd5080c3e096786bea6 , < 3e04596cba8a86cbff9c3f4bf0a524a3a488773c (git)
Affected: 0ca100ff4df64f5d0f6c1dd5080c3e096786bea6 , < 49875b360c2b83a3c226e189c502e501d83e6445 (git)
Affected: 0ca100ff4df64f5d0f6c1dd5080c3e096786bea6 , < d179a868dd755b0cfcf7582e00943d702b9943b8 (git)

Linux

Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.23 , ≤ 6.18.* (semver)
Unaffected: 6.19.13 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/rxrpc/key.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3e04596cba8a86cbff9c3f4bf0a524a3a488773c",
              "status": "affected",
              "version": "0ca100ff4df64f5d0f6c1dd5080c3e096786bea6",
              "versionType": "git"
            },
            {
              "lessThan": "49875b360c2b83a3c226e189c502e501d83e6445",
              "status": "affected",
              "version": "0ca100ff4df64f5d0f6c1dd5080c3e096786bea6",
              "versionType": "git"
            },
            {
              "lessThan": "d179a868dd755b0cfcf7582e00943d702b9943b8",
              "status": "affected",
              "version": "0ca100ff4df64f5d0f6c1dd5080c3e096786bea6",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/rxrpc/key.c"
          ],
          "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": "6.18.*",
              "status": "unaffected",
              "version": "6.18.23",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.23",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.13",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix RxGK token loading to check bounds\n\nrxrpc_preparse_xdr_yfs_rxgk() reads the raw key length and ticket length\nfrom the XDR token as u32 values and passes each through round_up(x, 4)\nbefore using the rounded value for validation and allocation.  When the raw\nlength is \u003e= 0xfffffffd, round_up() wraps to 0, so the bounds check and\nkzalloc both use 0 while the subsequent memcpy still copies the original\n~4 GiB value, producing a heap buffer overflow reachable from an\nunprivileged add_key() call.\n\nFix this by:\n\n (1) Rejecting raw key lengths above AFSTOKEN_GK_KEY_MAX and raw ticket\n     lengths above AFSTOKEN_GK_TOKEN_MAX before rounding, consistent with\n     the caps that the RxKAD path already enforces via AFSTOKEN_RK_TIX_MAX.\n\n (2) Sizing the flexible-array allocation from the validated raw key\n     length via struct_size_t() instead of the rounded value.\n\n (3) Caching the raw lengths so that the later field assignments and\n     memcpy calls do not re-read from the token, eliminating a class of\n     TOCTOU re-parse.\n\nThe control path (valid token with lengths within bounds) is unaffected."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-24T14:44:56.204Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3e04596cba8a86cbff9c3f4bf0a524a3a488773c"
        },
        {
          "url": "https://git.kernel.org/stable/c/49875b360c2b83a3c226e189c502e501d83e6445"
        },
        {
          "url": "https://git.kernel.org/stable/c/d179a868dd755b0cfcf7582e00943d702b9943b8"
        }
      ],
      "title": "rxrpc: Fix RxGK token loading to check bounds",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31641",
    "datePublished": "2026-04-24T14:44:56.204Z",
    "dateReserved": "2026-03-09T15:48:24.126Z",
    "dateUpdated": "2026-04-24T14:44:56.204Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-31641",
      "date": "2026-04-25",
      "epss": "0.00017",
      "percentile": "0.04073"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-31641\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-04-24T15:16:43.463\",\"lastModified\":\"2026-04-24T17:51:40.810\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nrxrpc: Fix RxGK token loading to check bounds\\n\\nrxrpc_preparse_xdr_yfs_rxgk() reads the raw key length and ticket length\\nfrom the XDR token as u32 values and passes each through round_up(x, 4)\\nbefore using the rounded value for validation and allocation.  When the raw\\nlength is \u003e= 0xfffffffd, round_up() wraps to 0, so the bounds check and\\nkzalloc both use 0 while the subsequent memcpy still copies the original\\n~4 GiB value, producing a heap buffer overflow reachable from an\\nunprivileged add_key() call.\\n\\nFix this by:\\n\\n (1) Rejecting raw key lengths above AFSTOKEN_GK_KEY_MAX and raw ticket\\n     lengths above AFSTOKEN_GK_TOKEN_MAX before rounding, consistent with\\n     the caps that the RxKAD path already enforces via AFSTOKEN_RK_TIX_MAX.\\n\\n (2) Sizing the flexible-array allocation from the validated raw key\\n     length via struct_size_t() instead of the rounded value.\\n\\n (3) Caching the raw lengths so that the later field assignments and\\n     memcpy calls do not re-read from the token, eliminating a class of\\n     TOCTOU re-parse.\\n\\nThe control path (valid token with lengths within bounds) is unaffected.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/3e04596cba8a86cbff9c3f4bf0a524a3a488773c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/49875b360c2b83a3c226e189c502e501d83e6445\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d179a868dd755b0cfcf7582e00943d702b9943b8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}

FKIE_CVE-2026-31641

Vulnerability from fkie_nvd - Published: 2026-04-24 15:16 - Updated: 2026-04-24 17:51

Severity ?

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/3e04596cba8a86cbff9c3f4bf0a524a3a488773c
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/49875b360c2b83a3c226e189c502e501d83e6445
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d179a868dd755b0cfcf7582e00943d702b9943b8

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix RxGK token loading to check bounds\n\nrxrpc_preparse_xdr_yfs_rxgk() reads the raw key length and ticket length\nfrom the XDR token as u32 values and passes each through round_up(x, 4)\nbefore using the rounded value for validation and allocation.  When the raw\nlength is \u003e= 0xfffffffd, round_up() wraps to 0, so the bounds check and\nkzalloc both use 0 while the subsequent memcpy still copies the original\n~4 GiB value, producing a heap buffer overflow reachable from an\nunprivileged add_key() call.\n\nFix this by:\n\n (1) Rejecting raw key lengths above AFSTOKEN_GK_KEY_MAX and raw ticket\n     lengths above AFSTOKEN_GK_TOKEN_MAX before rounding, consistent with\n     the caps that the RxKAD path already enforces via AFSTOKEN_RK_TIX_MAX.\n\n (2) Sizing the flexible-array allocation from the validated raw key\n     length via struct_size_t() instead of the rounded value.\n\n (3) Caching the raw lengths so that the later field assignments and\n     memcpy calls do not re-read from the token, eliminating a class of\n     TOCTOU re-parse.\n\nThe control path (valid token with lengths within bounds) is unaffected."
    }
  ],
  "id": "CVE-2026-31641",
  "lastModified": "2026-04-24T17:51:40.810",
  "metrics": {},
  "published": "2026-04-24T15:16:43.463",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3e04596cba8a86cbff9c3f4bf0a524a3a488773c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/49875b360c2b83a3c226e189c502e501d83e6445"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d179a868dd755b0cfcf7582e00943d702b9943b8"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}

GHSA-P4PM-X7CH-5MVC

Vulnerability from github – Published: 2026-04-24 15:32 – Updated: 2026-04-24 15:32

Details

In the Linux kernel, the following vulnerability has been resolved:

rxrpc: Fix RxGK token loading to check bounds

rxrpc_preparse_xdr_yfs_rxgk() reads the raw key length and ticket length from the XDR token as u32 values and passes each through round_up(x, 4) before using the rounded value for validation and allocation. When the raw length is >= 0xfffffffd, round_up() wraps to 0, so the bounds check and kzalloc both use 0 while the subsequent memcpy still copies the original ~4 GiB value, producing a heap buffer overflow reachable from an unprivileged add_key() call.

Fix this by:

(1) Rejecting raw key lengths above AFSTOKEN_GK_KEY_MAX and raw ticket lengths above AFSTOKEN_GK_TOKEN_MAX before rounding, consistent with the caps that the RxKAD path already enforces via AFSTOKEN_RK_TIX_MAX.

(2) Sizing the flexible-array allocation from the validated raw key length via struct_size_t() instead of the rounded value.

(3) Caching the raw lengths so that the later field assignments and memcpy calls do not re-read from the token, eliminating a class of TOCTOU re-parse.

The control path (valid token with lengths within bounds) is unaffected.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-31641"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-24T15:16:43Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix RxGK token loading to check bounds\n\nrxrpc_preparse_xdr_yfs_rxgk() reads the raw key length and ticket length\nfrom the XDR token as u32 values and passes each through round_up(x, 4)\nbefore using the rounded value for validation and allocation.  When the raw\nlength is \u003e= 0xfffffffd, round_up() wraps to 0, so the bounds check and\nkzalloc both use 0 while the subsequent memcpy still copies the original\n~4 GiB value, producing a heap buffer overflow reachable from an\nunprivileged add_key() call.\n\nFix this by:\n\n (1) Rejecting raw key lengths above AFSTOKEN_GK_KEY_MAX and raw ticket\n     lengths above AFSTOKEN_GK_TOKEN_MAX before rounding, consistent with\n     the caps that the RxKAD path already enforces via AFSTOKEN_RK_TIX_MAX.\n\n (2) Sizing the flexible-array allocation from the validated raw key\n     length via struct_size_t() instead of the rounded value.\n\n (3) Caching the raw lengths so that the later field assignments and\n     memcpy calls do not re-read from the token, eliminating a class of\n     TOCTOU re-parse.\n\nThe control path (valid token with lengths within bounds) is unaffected.",
  "id": "GHSA-p4pm-x7ch-5mvc",
  "modified": "2026-04-24T15:32:36Z",
  "published": "2026-04-24T15:32:36Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31641"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3e04596cba8a86cbff9c3f4bf0a524a3a488773c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/49875b360c2b83a3c226e189c502e501d83e6445"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d179a868dd755b0cfcf7582e00943d702b9943b8"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

CVE-2026-31641 (GCVE-0-2026-31641)

FKIE_CVE-2026-31641

GHSA-P4PM-X7CH-5MVC

Tags

Sightings

Nomenclature