VulnerabilityPublished 22 Aug 2026Updated 9 Oct 2026

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

Affects Linux kernelSource GCVE Database

Not known to be exploited · fixed in 5.15.0-1117.124~20.04.1 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 14:05 UTC

Severity

Medium

Rated by Threat Radar · 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 5.15.0-1117.124~20.04.1, 5.15.0-1123.132~20.04.1, 5.15.0-1122.131~20.04.1 +26

Exploitation evidence

Disclosed: evidence found.
CVE published 22 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.

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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-38.38 23 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected 6.17.0-1003.3 – 7.0.0-1017.17 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected 7.0.0-1003.3 – 7.0.0-1016.16 9 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 13 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected 7.0.0-1002.3 – 7.0.0-1008.9 6 affected builds	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-aws kernel versions to resolve this issue. After applying the update, a system reboot is required to complete remediation. No additional mitigation steps are indicated by the vendor advisory.

Description

A vulnerability in the Linux kernel's Open vSwitch (OVS) component was resolved that involved improper handling of update replies for flows with mismatched identifiers. The issue occurs because the preallocated reply buffer may be too small when the flow identifier used for the reply differs from the request identifier, potentially causing a kernel bug triggered by a buffer size error. This flaw could lead to a kernel crash during flow updates. Multiple specific linux-aws kernel versions are affected. A patch is available to address this issue.

Impact

This vulnerability can cause a denial of service by triggering a kernel BUG_ON condition during Open vSwitch flow updates, leading to a system crash. There is no indication of privilege escalation or remote code execution. The impact is limited to kernel stability disruption.

Summary

The vulnerability in the Linux kernel's Open vSwitch (OVS) subsystem arises from ovs_flow_cmd_new() preallocating an optional reply socket buffer (skb) before acquiring ovs_mutex and before determining which existing flow will be updated. Normally, the skb size is based on the request flow identifier, which also becomes the inserted flow's identifier. However, for update requests using a UFID (unique flow identifier), a lookup may fall back to the flow key lookup, which can find a different existing flow. The reply function ovs_flow_cmd_fill_info() writes the matched flow's identifier, not the request identifier, potentially requiring a larger skb. If the preallocated skb is too small, the fill fails with -EMSGSIZE and triggers a BUG_ON error, causing a kernel crash. The fix reallocates the reply skb after resolving the update target but before replacing actions, allowing the request to fail cleanly if the allocation fails.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 05:23 UTC

Technical details

References

Community reviews

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