CVE-2026-98301: Linux kernel · net: bridge: mst: move switchdev call outside rcu
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in d5c4ee1fa4e83a12afc051c831936cd8e006cde3 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in d5c4ee1fa4e83a12afc051c831936cd8e006cde3, c40ed3e884c8dc0350f26484030438ef24208ff1, b9661fd2423fc25e91e0517ecc0b6156ad83e3a8 +7
Exploitation evidence
Disclosed: evidence found.
CVE published 6 Oct 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 |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix is available and has been applied in Linux kernel versions 6.1.189, 6.6.158, 6.9, 6.10, and corresponding commits. Users should upgrade to these fixed versions to remediate the issue.
Description
A vulnerability in the Linux kernel's network bridge MST (Multiple Spanning Tree) implementation involves improper handling of switchdev calls within an RCU read-side critical section. The function br_mst_set_state() calls switchdev_port_attr_set() while holding rcu_read_lock(), which can invoke a blocking notifier chain and potentially sleep, violating RCU constraints. The issue has been fixed by moving the switchdev call outside the RCU section and ensuring rtnl lock is held.
References
- git.kernel.org/stable/c/b9661fd2423fc25e91e0517ecc0b6156ad83e3a8 (opens in a new tab)
- git.kernel.org/stable/c/6b431b63219853eef4054e2f1cb073d2ca2059b4 (opens in a new tab)
- git.kernel.org/stable/c/abf734d150c61acfdfee102169d0e5d1c482e285 (opens in a new tab)
- git.kernel.org/stable/c/d5c4ee1fa4e83a12afc051c831936cd8e006cde3 (opens in a new tab)
- git.kernel.org/stable/c/c40ed3e884c8dc0350f26484030438ef24208ff1 (opens in a new tab)
- git.kernel.org/stable/c/18a6fe05fb6e18de29fa90d388bb34044114b3d8 (opens in a new tab)