CVE-2026-31678: Linux kernel · openvswitch: defer tunnel netdev_put to RCU release
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in bbe7bd722bfaea36aab3da6cc60fb4a05c644643 : patch Linux kernel soon.
Data as of 26 Oct 2026, 12:55 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.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in bbe7bd722bfaea36aab3da6cc60fb4a05c644643, b8c56a3fc5d879c0928f207a756b0f067f06c6a8, 6931d21f87bc6d657f145798fad0bf077b82486c +3
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 25 Apr 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
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
Description
In the Linux kernel, the following vulnerability has been resolved: openvswitch: defer tunnel netdev_put to RCU release ovs_netdev_tunnel_destroy() may run after NETDEV_UNREGISTER already detached the device. Dropping the netdev reference in destroy can race with concurrent readers that still observe vport->dev. Do not release vport->dev in ovs_netdev_tunnel_destroy(). Instead, let vport_netdev_free() drop the reference from the RCU callback, matching the non-tunnel destroy path and avoiding additional synchronization under RTNL.
References
- git.kernel.org/stable/c/9d56aced21fb9c104e8a3f3be9b21fbafe448ffc (opens in a new tab)
- git.kernel.org/stable/c/42f0d3d81209654c08ffdde5a34b9b92d2645896 (opens in a new tab)
- git.kernel.org/stable/c/bbe7bd722bfaea36aab3da6cc60fb4a05c644643 (opens in a new tab)
- git.kernel.org/stable/c/98b726ab5e2a4811e27c28e4d041f75bba147eab (opens in a new tab)
- git.kernel.org/stable/c/b8c56a3fc5d879c0928f207a756b0f067f06c6a8 (opens in a new tab)
- git.kernel.org/stable/c/6931d21f87bc6d657f145798fad0bf077b82486c (opens in a new tab)