CVE-2026-74339 (GCVE-0-2026-74339)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:58 – Updated: 2026-08-17 05:17
VLAI
Title
ALSA: seq: Clear variable event pointer on read
Summary
In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: Clear variable event pointer on read snd_seq_read() copies a queued variable-length event header to userspace before expanding the payload. Queued variable-length events use SNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first extension cell. The read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the copy, but it leaves data.ext.ptr untouched. A userspace sequencer client can therefore write a direct variable event to itself and read back the extension-cell kernel address from the returned header. Clear the temporary header pointer before copy_to_user(). The original queued event remains unchanged and is still passed to snd_seq_expand_var_event(), so payload expansion keeps using the internal chain.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 14fe4f75fd5309d6b75f8e840ada88912b374207 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < f29243c211928114f8b906e0a3fee77c236f14c8 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < e0c3edd86414534cfd179fefe45b38c29c01ae7a (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 6b52211eba213c461f68922708a99d8190c1fcd5 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < c2ac9287e89916da684c2a548798351e63eb59ee (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 705dd6dcbc0ea87351c660c1a6443f85f1001c76 (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.12
Unaffected: 0 , < 2.6.12 (semver)
Unaffected: 5.15.212 , ≤ 5.15.* (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (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": [
            "sound/core/seq/seq_clientmgr.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "14fe4f75fd5309d6b75f8e840ada88912b374207",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "f29243c211928114f8b906e0a3fee77c236f14c8",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "e0c3edd86414534cfd179fefe45b38c29c01ae7a",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "6b52211eba213c461f68922708a99d8190c1fcd5",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "c2ac9287e89916da684c2a548798351e63eb59ee",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            },
            {
              "lessThan": "705dd6dcbc0ea87351c660c1a6443f85f1001c76",
              "status": "affected",
              "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "sound/core/seq/seq_clientmgr.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": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.212",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "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\nALSA: seq: Clear variable event pointer on read\n\nsnd_seq_read() copies a queued variable-length event header to userspace\nbefore expanding the payload. Queued variable-length events use\nSNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first\nextension cell.\n\nThe read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the\ncopy, but it leaves data.ext.ptr untouched. A userspace sequencer client\ncan therefore write a direct variable event to itself and read back the\nextension-cell kernel address from the returned header.\n\nClear the temporary header pointer before copy_to_user(). The original\nqueued event remains unchanged and is still passed to\nsnd_seq_expand_var_event(), so payload expansion keeps using the\ninternal chain."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:17:31.258Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/14fe4f75fd5309d6b75f8e840ada88912b374207"
        },
        {
          "url": "https://git.kernel.org/stable/c/f29243c211928114f8b906e0a3fee77c236f14c8"
        },
        {
          "url": "https://git.kernel.org/stable/c/e0c3edd86414534cfd179fefe45b38c29c01ae7a"
        },
        {
          "url": "https://git.kernel.org/stable/c/6b52211eba213c461f68922708a99d8190c1fcd5"
        },
        {
          "url": "https://git.kernel.org/stable/c/74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b"
        },
        {
          "url": "https://git.kernel.org/stable/c/c2ac9287e89916da684c2a548798351e63eb59ee"
        },
        {
          "url": "https://git.kernel.org/stable/c/705dd6dcbc0ea87351c660c1a6443f85f1001c76"
        }
      ],
      "title": "ALSA: seq: Clear variable event pointer on read",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74339",
    "datePublished": "2026-08-15T05:58:29.888Z",
    "dateReserved": "2026-08-15T05:44:03.885Z",
    "dateUpdated": "2026-08-17T05:17:31.258Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74339",
      "date": "2026-09-21",
      "epss": "0.00173",
      "percentile": "0.06986"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "sound/core/seq/seq_clientmgr.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "14fe4f75fd5309d6b75f8e840ada88912b374207",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "f29243c211928114f8b906e0a3fee77c236f14c8",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "e0c3edd86414534cfd179fefe45b38c29c01ae7a",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "6b52211eba213c461f68922708a99d8190c1fcd5",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "c2ac9287e89916da684c2a548798351e63eb59ee",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "705dd6dcbc0ea87351c660c1a6443f85f1001c76",
                    "status": "affected",
                    "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "sound/core/seq/seq_clientmgr.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": "5.15.*",
                    "status": "unaffected",
                    "version": "5.15.212",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.1.*",
                    "status": "unaffected",
                    "version": "6.1.178",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.6.*",
                    "status": "unaffected",
                    "version": "6.6.145",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.12.*",
                    "status": "unaffected",
                    "version": "6.12.97",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "6.18.*",
                    "status": "unaffected",
                    "version": "6.18.40",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "7.1.*",
                    "status": "unaffected",
                    "version": "7.1.5",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "7.2",
                    "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\nALSA: seq: Clear variable event pointer on read\n\nsnd_seq_read() copies a queued variable-length event header to userspace\nbefore expanding the payload. Queued variable-length events use\nSNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first\nextension cell.\n\nThe read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the\ncopy, but it leaves data.ext.ptr untouched. A userspace sequencer client\ncan therefore write a direct variable event to itself and read back the\nextension-cell kernel address from the returned header.\n\nClear the temporary header pointer before copy_to_user(). The original\nqueued event remains unchanged and is still passed to\nsnd_seq_expand_var_event(), so payload expansion keeps using the\ninternal chain."
          }
        ],
        "id": "CVE-2026-74339",
        "lastModified": "2026-08-17T06:19:28.357",
        "metrics": {},
        "published": "2026-08-15T06:22:34.850",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/14fe4f75fd5309d6b75f8e840ada88912b374207"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/6b52211eba213c461f68922708a99d8190c1fcd5"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/705dd6dcbc0ea87351c660c1a6443f85f1001c76"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/c2ac9287e89916da684c2a548798351e63eb59ee"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/e0c3edd86414534cfd179fefe45b38c29c01ae7a"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/f29243c211928114f8b906e0a3fee77c236f14c8"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-20T18:16:10+00:00",
      "cve": "CVE-2026-74339",
      "id": "CVE-2026-74339",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ALSA: seq: Clear variable event pointer on read",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74339.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "low",
      "current_release_date": "2026-09-03T00:07:08Z",
      "cve": "CVE-2026-74339",
      "id": "CVE-2026-74339",
      "initial_release_date": "2026-09-03T00:07:08Z",
      "product_status:known_affected": "269",
      "product_status:known_not_affected": "93",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74339",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74339.json",
      "version": "2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.



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.