CVE-2026-89736: Linux kernel · usb: gadget: u_audio: Fix use-after-free on sound card disconnect
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% 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:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 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.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available that defers freeing the snd_uac_chip structure until all references to the ALSA sound card are released. Users should update to patched Linux kernel versions that include this fix. No additional mitigation is indicated by the vendor advisory.
Description
A use-after-free vulnerability in the Linux kernel's USB gadget audio driver (u_audio) was fixed. The issue occurred when the sound card was disconnected and the underlying context was freed while ALSA control elements remained open in userspace. This caused callbacks to dereference freed memory, leading to memory corruption. The fix defers destruction of the context until all references are released.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89736 (opens in a new tab)
- git.kernel.org/stable/c/4e747c864a88537e18b1ffc19a1954c9686bb8e1 (opens in a new tab)
- git.kernel.org/stable/c/79a92896e2bb9471550c56fc23d8d93592f04c27 (opens in a new tab)
- git.kernel.org/stable/c/858965947081d10d41d9a1010a540d3d5eea958b (opens in a new tab)
- git.kernel.org/stable/c/c74ff0b1a0fca53d3ac185873c87d6a719b30a47 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89736 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89736 (opens in a new tab)
- git.kernel.org/linus/858965947081d10d41d9a1010a540d3d5eea958b (opens in a new tab)