CVE-2026-74691: Linux kernel · net: thunderbolt: Tear down DMA paths before stopping the rings
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High · fixed in 5.15.0-1117.124~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 17% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +27
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 22 Aug 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
Upgrade to a fixed release listed under Affected software.
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 corrects the teardown sequence to deactivate DMA paths before stopping the rings. Users should apply the updated Linux Azure kernel versions that include this fix. Patch status is confirmed by the resolution of the vulnerability in the Linux kernel source. No alternative mitigations are indicated.
Description
A vulnerability in the Linux kernel's thunderbolt network driver (net: thunderbolt) involves improper teardown sequencing of DMA paths and rings. The teardown process stops rings and frees frame buffers before disabling DMA paths, causing the 'pending' bit to never clear and resulting in timeouts. This can lead to the XDomain control channel going down, requiring a power cycle to recover. The issue affects specific Azure Linux kernel versions. The vulnerability has been resolved by correcting the teardown order to deactivate DMA paths before stopping the rings.
References
- nvd.nist.gov/vuln/detail/CVE-2026-74691 (opens in a new tab)
- git.kernel.org/stable/c/0da9a6d27155ad072dd76db8cd637feead99a0e0 (opens in a new tab)
- git.kernel.org/stable/c/103a9b663ac1cacb8465aeff18f84a247154a562 (opens in a new tab)
- git.kernel.org/stable/c/4dd71cb0d23d40cb58fe4261c7bd183dca66caa0 (opens in a new tab)
- git.kernel.org/stable/c/68bf02b6b4ad3f748c6db71fd77b6c0402d252f4 (opens in a new tab)
- git.kernel.org/stable/c/7cce39109206bc5497e0953806563644b88bfc44 (opens in a new tab)
- git.kernel.org/stable/c/9a482b2b117e5fa656b6d24fc01799e8ac2d4368 (opens in a new tab)
- git.kernel.org/stable/c/b5a21615f627c48dafaa6ef82a34a5b97a4352aa (opens in a new tab)
- ubuntu.com/security/CVE-2026-74691 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-74691 (opens in a new tab)
- ubuntu.com/security/notices/USN-8878-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8877-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8875-2 (opens in a new tab)