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Fencer Vulns
no cvss —

CVE-2026-74664 json

net: openvswitch: reallocate update replies for mismatched IDs

published 2026-08-22 2 mo ago modified 2026-11-06 2 d ago also EUVD-2026-64351

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

net: openvswitch: reallocate update replies for mismatched IDs

ovs_flow_cmd_new() preallocates the optional reply skb before it takes ovs_mutex and before it knows which existing flow will be updated.

That is normally fine because the skb is sized from the request flow identifier. That identifier also becomes the inserted flow's identifier. For updates, however, a request with a UFID may miss the UFID lookup and then fall back to the flow key lookup. That lookup can legitimately find an existing key-identified flow. UFIDs are optional and the flow key is the primary identifier.

For echoed replies, ovs_flow_cmd_fill_info() writes the matched flow's identifier, not the request identifier used for the preallocation. A short request UFID can therefore leave too little room for the key identifier. The fill can then fail with -EMSGSIZE and hit the BUG_ON(error < 0) in the update path.

Once the update target has been resolved, reallocate the reply skb if the matched flow needs a larger reply than the request identifier allowed. Do this before replacing the actions so the request can still fail cleanly if the rare extra allocation fails.

Patch / fix

  • Linux Linux 5.10.265, 5.15.216, 6.1.183, 6.6.152, 6.12.104, 6.18.45, 7.1.9, 7.2
  • linux Debian 12 6.1.187-1
  • linux Debian 13 6.12.105-1
  • linux Debian 14 7.1.9-1
  • linux-6.12 Debian 12 6.12.107-1~deb12u1

debian advisories DEBIAN-CVE-2026-74664

  • linux Ubuntu 22.04 LTS 5.15.0-198.208
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1113.119
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1111.115

ubuntu advisories UBUNTU-CVE-2026-74664

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel Azure Linux 3.0 6.6.152.1-1

azure linux advisories AZL-97154

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-74664 updated cvss 5.5

kernel: net: openvswitch: reallocate update replies for mismatched IDs

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 d ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.