CVE-2026-72389: Linux kernel · bridge: stp: Fix a potential use-after-free when deleting a bridge
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 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
- 0.1% chance of exploitation in 30 days – higher than 5% 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 +42
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 15 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 patch is available and should be applied to affected Linux kernel versions. The vendor advisory confirms that this issue has been fixed. Users should update to patched kernel versions to remediate this vulnerability.
Description
A use-after-free vulnerability in the Linux kernel's bridge STP (Spanning Tree Protocol) implementation was fixed. The issue arises because the topology change timer could be armed while the bridge is administratively down, leading to a use-after-free condition when the bridge is deleted. The fix adds a missing check to prevent timers from being armed in this state and synchronously shuts down the timers upon bridge deletion.
References
- nvd.nist.gov/vuln/detail/CVE-2026-72389 (opens in a new tab)
- git.kernel.org/stable/c/297a747f59bff6573196d7236178144d66524e68 (opens in a new tab)
- git.kernel.org/stable/c/2a00517db8de4be7df3d483b215c5544fb30a191 (opens in a new tab)
- git.kernel.org/stable/c/39283907a25e5caf0f2bd2947f6e56644b01e2b7 (opens in a new tab)
- git.kernel.org/stable/c/40cbfa3a28e0919469d1b086629bb3ce38a83593 (opens in a new tab)
- git.kernel.org/stable/c/4c40eec06eeac37c58e47a6058eb32901218d5d4 (opens in a new tab)
- git.kernel.org/stable/c/b4b3458ef88df4798632619f018791d4344bcd92 (opens in a new tab)
- git.kernel.org/stable/c/c86579b0a2d201792bcb59316629f4ba4758cfc8 (opens in a new tab)
- ubuntu.com/security/CVE-2026-72389 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-72389 (opens in a new tab)
- git.kernel.org/linus/2a00517db8de4be7df3d483b215c5544fb30a191 (opens in a new tab)
- ubuntu.com/security/notices/USN-8876-1 (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-8888-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8889-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8887-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8886-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8888-2 (opens in a new tab)