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.

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Linux
  • Linux Kernel

No data.

No data.

References
Link Providers
https://git.kernel.org/stable/c/14fe4f75fd5309d6b75f8e840ada88912b374207 cve-icon cve-icon
https://git.kernel.org/stable/c/6b52211eba213c461f68922708a99d8190c1fcd5 cve-icon cve-icon
https://git.kernel.org/stable/c/705dd6dcbc0ea87351c660c1a6443f85f1001c76 cve-icon cve-icon
https://git.kernel.org/stable/c/74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b cve-icon cve-icon
https://git.kernel.org/stable/c/c2ac9287e89916da684c2a548798351e63eb59ee cve-icon cve-icon
https://git.kernel.org/stable/c/e0c3edd86414534cfd179fefe45b38c29c01ae7a cve-icon cve-icon
https://git.kernel.org/stable/c/f29243c211928114f8b906e0a3fee77c236f14c8 cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2026081557-CVE-2026-74339-9cd8@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-74339 cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-74339 cve-icon
History

Sat, 22 Aug 2026 01:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200

Fri, 21 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-824
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Sat, 15 Aug 2026 13:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-200

Sat, 15 Aug 2026 06:15:00 +0000

Type Values Removed Values Added
Description 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.
Title ALSA: seq: Clear variable event pointer on read
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-08-15T05:58:29.888Z

Updated: 2026-08-17T05:17:31.258Z

Reserved: 2026-08-15T05:44:03.885Z

Link: CVE-2026-74339

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-15T06:22:34.850

Modified: 2026-08-17T06:19:28.357

Link: CVE-2026-74339

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-15T00:00:00Z

Links: CVE-2026-74339 - Bugzilla