CVE-2026-89738: Linux kernel · usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 8% 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 properly shuts down the polled-VBUS timer and work cycle during driver removal and probe failure to prevent use-after-free. Users should update to a Linux kernel version that includes this patch. Since this is a kernel driver issue, applying the official kernel update from the vendor or distribution is the recommended remediation.
Description
A use-after-free vulnerability in the Linux kernel's at91_udc USB gadget driver was resolved. The issue occurs because a polled-VBUS timer and work cycle continue to reference a device context (udc) after it has been freed during driver removal or probe failure. This can lead to dereferencing freed memory, causing potential system instability or compromise. The fix involves properly shutting down the timer and work cycle during driver removal and probe failure paths to prevent use-after-free conditions.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89738 (opens in a new tab)
- git.kernel.org/stable/c/51a311eb97e91ce1aed3005cb71ccb2e30f8cce8 (opens in a new tab)
- git.kernel.org/stable/c/557ef547d49ff5e6026a4d39bdd3113bd81d7688 (opens in a new tab)
- git.kernel.org/stable/c/a2a602cb1e28d76a5398cec3fa21b0110385f501 (opens in a new tab)
- git.kernel.org/stable/c/c27d13ce4bab80fbdf6523928071b6c24b37606c (opens in a new tab)
- ubuntu.com/security/CVE-2026-89738 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89738 (opens in a new tab)
- git.kernel.org/linus/c27d13ce4bab80fbdf6523928071b6c24b37606c (opens in a new tab)
- git.kernel.org/stable/c/723d73b245843d4fff4c3f42e857c78c2b2d414e (opens in a new tab)