VulnerabilityPublished 25 Jul 2026Updated 29 Oct 2026

CVE-2026-64479: Linux kernel · ALSA: seq: Fix uninitialised heap leak in snd_seq_event_dup()

Affects Linux kernelSource GCVE Database

Compare

Not known to be exploited · fixed in 6.8.0-147.147 : update Linux kernel when convenient.

Data as of 30 Oct 2026, 06:59 UTC

Severity

Medium

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 6.8.0-147.147, 6.8.0-1067.70, 7.0.0-1012.12~24.04.1 +28

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Patches and advisories

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected <7.0.0-31.31	Fixed in 7.0.0-31.31
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected <7.0.0-1012.12	Fixed in 7.0.0-1012.12
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected <7.0.0-1014.14	Fixed in 7.0.0-1014.14
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected <7.0.0-1013.13	Fixed in 7.0.0-1013.13
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected <7.0.0-1011.11	Fixed in 7.0.0-1011.11
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected <7.0.0-1006.7	Fixed in 7.0.0-1006.7

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and has been applied in multiple Linux kernel versions including 6.8.0-147.147, 6.8.0-1067.70, 7.0.0-1012.12~24.04.1, and others. Users and administrators should update to these fixed kernel versions to remediate the vulnerability. No additional mitigation steps are required beyond applying the official kernel updates.

Description

CVE-2026-64479 is a vulnerability in the Linux kernel ALSA subsystem where an uninitialized heap memory leak occurs in the snd_seq_event_dup() function. This flaw allows stale kernel heap data to be copied to user space via the /dev/snd/seq interface under certain conditions, potentially leaking sensitive kernel memory to unprivileged users. The issue arises because a trailing word in a copied event structure is not properly zeroed for legacy events, leading to exposure of leftover or uninitialized data. This vulnerability has been fixed in several Linux kernel versions.

Impact

An unprivileged local user with access to the ALSA sequencer interface (/dev/snd/seq) can obtain a 4-byte kernel heap information leak. This leak exposes stale or uninitialized kernel heap memory, which could potentially aid further attacks such as kernel memory disclosure or exploitation. No evidence of active exploitation is reported. The impact is limited to information disclosure without direct privilege escalation or code execution.

Summary

The vulnerability in the Linux kernel ALSA subsystem involves the snd_seq_event_dup() function, which copies an incoming event into a pool cell. In UMP-enabled builds, a trailing word in the cell is cleared only if the copied size is less than the size of the event structure. For legacy events, this condition is false, leaving the trailing word uninitialized and containing stale kernel heap data. Since the cell pool is allocated with kvmalloc() without zeroing and cells are reused, this stale data can be leaked to user space when delivered to a UMP client that disables conversion. This results in a 4-byte kernel heap information leak to unprivileged clients accessing /dev/snd/seq. The fix involves comparing the copied size against the size of the UMP cell instead, ensuring the trailing word is zeroed for all shorter events. Multiple Linux kernel versions have been patched to address this issue.

References

Community reviews

Loading reviews…