Incorrect Calculation of Buffer Size Affecting kernel-64k-debug package, versions *


Severity

Recommended
low

Based on CentOS security rating.

Threat Intelligence

EPSS
0.18% (8th percentile)

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  • Snyk IDSNYK-CENTOS10-KERNEL64KDEBUG-19238776
  • published25 Aug 2026
  • disclosed22 Aug 2026

Introduced: 22 Aug 2026

NewCVE-2026-74664  (opens in a new tab)
CWE-131  (opens in a new tab)

How to fix?

There is no fixed version for Centos:10 kernel-64k-debug.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-64k-debug package and not the kernel-64k-debug package as distributed by Centos. See How to fix? for Centos:10 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1