VulnerabilityPublished 25 Jun 2026Updated 6 Nov 2026

CVE-2026-53241: Linux kernel · ALSA: seq: dummy: fix UMP event stack overread

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in a7ef78a2c536242ccb7a4429da01580b2409bb24 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:49 UTC

Severity

Unrated

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

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in a7ef78a2c536242ccb7a4429da01580b2409bb24, 6676b6063440561db600494049ce7ffb695c8cc4, 6671a46144f880c5a167930ebb14c12f3d059fe9 +1

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jun 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 6 Nov 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 Linux kernel to a7ef78a2c536242ccb7a4429da01580b2409bb24, 6676b6063440561db600494049ce7ffb695c8cc4, 6671a46144f880c5a167930ebb14c12f3d059fe9 or 2b5ff4db5d7aa5b981d966df02e687f79ad7b311.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 32cb23a0f911317cdb5030035e49a204aa86fef5, < a7ef78a2c536242ccb7a4429da01580b2409bb24	Fixed in a7ef78a2c536242ccb7a4429da01580b2409bb24
LinuxLinux	Affected ≥ 32cb23a0f911317cdb5030035e49a204aa86fef5, < 6676b6063440561db600494049ce7ffb695c8cc4	Fixed in 6676b6063440561db600494049ce7ffb695c8cc4
LinuxLinux	Affected ≥ 32cb23a0f911317cdb5030035e49a204aa86fef5, < 6671a46144f880c5a167930ebb14c12f3d059fe9	Fixed in 6671a46144f880c5a167930ebb14c12f3d059fe9
LinuxLinux	Affected ≥ 32cb23a0f911317cdb5030035e49a204aa86fef5, < 2b5ff4db5d7aa5b981d966df02e687f79ad7b311	Fixed in 2b5ff4db5d7aa5b981d966df02e687f79ad7b311
LinuxLinux	Affected =6.10	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: seq: dummy: fix UMP event stack overread The dummy sequencer port forwards events by copying an incoming struct snd_seq_event into a stack temporary, rewriting source and destination, and dispatching the temporary to subscribers. That legacy event storage is smaller than struct snd_seq_ump_event. When a UMP event reaches the dummy client, the copy leaves the UMP flag set but only provides legacy-sized stack storage. The subscriber delivery path then uses snd_seq_event_packet_size() and copies a UMP-sized packet from that stack object, reading past the end of the temporary. Use the existing union __snd_seq_event storage and copy the packet size reported for the incoming event before rewriting the common routing fields. This preserves the full UMP packet for UMP events while keeping legacy event handling unchanged.

References

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