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VulnerabilityPublished Updated

CVE-2026-31678: Linux kernel · openvswitch: defer tunnel netdev_put to RCU release

Affects Linux kernelSource CVE Database V5

0

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

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ a9020fde67a6eb77f8130feff633189f99264db1, < bbe7bd722bfaea36aab3da6cc60fb4a05c644643
Fixed in
  • bbe7bd722bfaea36aab3da6cc60fb4a05c644643
LinuxLinuxAffected
  • ≥ a9020fde67a6eb77f8130feff633189f99264db1, < b8c56a3fc5d879c0928f207a756b0f067f06c6a8
Fixed in
  • b8c56a3fc5d879c0928f207a756b0f067f06c6a8
LinuxLinuxAffected
  • ≥ a9020fde67a6eb77f8130feff633189f99264db1, < 6931d21f87bc6d657f145798fad0bf077b82486c
Fixed in
  • 6931d21f87bc6d657f145798fad0bf077b82486c
LinuxLinuxAffected
  • ≥ a9020fde67a6eb77f8130feff633189f99264db1, < 98b726ab5e2a4811e27c28e4d041f75bba147eab
Fixed in
  • 98b726ab5e2a4811e27c28e4d041f75bba147eab
LinuxLinuxAffected
  • ≥ a9020fde67a6eb77f8130feff633189f99264db1, < 42f0d3d81209654c08ffdde5a34b9b92d2645896
Fixed in
  • 42f0d3d81209654c08ffdde5a34b9b92d2645896
LinuxLinuxAffected
  • ≥ a9020fde67a6eb77f8130feff633189f99264db1, < 9d56aced21fb9c104e8a3f3be9b21fbafe448ffc
Fixed in
  • 9d56aced21fb9c104e8a3f3be9b21fbafe448ffc

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

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