VulnerabilityPublished 22 Aug 2026Updated 6 Nov 2026

CVE-2026-74664: Linux kernel · net: openvswitch: reallocate update replies for mismatched IDs

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in bd8ca84d48cd9a4f6fc63df26512c55e1d339927 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 17:48 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

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: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in bd8ca84d48cd9a4f6fc63df26512c55e1d339927, 20751193d83be2e9735d4faee71375691c09cd13, 23716dd9d8d46a5908536b73dc085e62f2b5c237 +5

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 74ed7ab9264c54471c7f057409d352052820d750, < bd8ca84d48cd9a4f6fc63df26512c55e1d339927	Fixed in bd8ca84d48cd9a4f6fc63df26512c55e1d339927
LinuxLinux	Affected ≥ 74ed7ab9264c54471c7f057409d352052820d750, < 20751193d83be2e9735d4faee71375691c09cd13	Fixed in 20751193d83be2e9735d4faee71375691c09cd13
LinuxLinux	Affected ≥ 74ed7ab9264c54471c7f057409d352052820d750, < 23716dd9d8d46a5908536b73dc085e62f2b5c237	Fixed in 23716dd9d8d46a5908536b73dc085e62f2b5c237
LinuxLinux	Affected ≥ 74ed7ab9264c54471c7f057409d352052820d750, < 696a0b9435fce9cf4f1e9ba7f6afa6bee96c97fc	Fixed in 696a0b9435fce9cf4f1e9ba7f6afa6bee96c97fc
LinuxLinux	Affected ≥ 74ed7ab9264c54471c7f057409d352052820d750, < 87d0c0040b5d4b61de51ae39132c4c46709f2f77	Fixed in 87d0c0040b5d4b61de51ae39132c4c46709f2f77
LinuxLinux	Affected ≥ 74ed7ab9264c54471c7f057409d352052820d750, < 69f40ccf85074981340847d650a9cbf9adabfbbe	Fixed in 69f40ccf85074981340847d650a9cbf9adabfbbe

AI-suggested

A fix is available and has been applied in the Linux kernel versions identified by the provided commit hashes. Users should update their Linux kernel to a version that includes these fixes to mitigate the vulnerability. No additional mitigation steps are indicated.

Description

CVE-2026-74664 is a vulnerability in the Linux kernel's Open vSwitch (OVS) component related to handling update replies for flows with mismatched identifiers. The issue arises because the reply socket buffer (skb) is preallocated based on the request's flow identifier before the actual flow to update is determined, which can lead to insufficient buffer size and a kernel bug triggered by a failed buffer fill operation. This has been fixed by reallocating the reply skb after resolving the correct flow to ensure adequate buffer size.

Impact

This flaw can cause a kernel BUG_ON condition during flow update operations in Open vSwitch, potentially leading to kernel crashes or instability. There is no indication of remote code execution or privilege escalation from the provided data. No known exploits in the wild have been reported.

Summary

The vulnerability in the Linux kernel's Open vSwitch implementation involves ovs_flow_cmd_new() preallocating a reply skb based on the request flow identifier before locking and flow resolution. When a request with a UFID misses the UFID lookup and falls back to a flow key lookup, the matched flow's identifier may require a larger reply skb than initially allocated. This mismatch can cause ovs_flow_cmd_fill_info() to fail with -EMSGSIZE and trigger a BUG_ON error in the update path. The fix reallocates the reply skb after determining the matched flow to prevent this failure.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Nov 2026, 17:48 UTC

Technical details

References

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