CVE-2026-53241: Linux kernel · ALSA: seq: dummy: fix UMP event stack overread
Source GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 26 Oct 2026, 12:55 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
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
- nvd.nist.gov/vuln/detail/CVE-2026-53241 (opens in a new tab)
- git.kernel.org/stable/c/2b5ff4db5d7aa5b981d966df02e687f79ad7b311 (opens in a new tab)
- git.kernel.org/stable/c/6671a46144f880c5a167930ebb14c12f3d059fe9 (opens in a new tab)
- git.kernel.org/stable/c/6676b6063440561db600494049ce7ffb695c8cc4 (opens in a new tab)
- git.kernel.org/stable/c/a7ef78a2c536242ccb7a4429da01580b2409bb24 (opens in a new tab)