PT-2026-64855 · Linux · Linux
CVE-2026-64531
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Published
2026-07-27
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Updated
2026-07-27
None
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In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: reject oversized nested action attrs
Open vSwitch stores generated flow actions as nlattrs, whose nla len
field is u16. Commit a1e64addf3ff ("net: openvswitch: remove
misbehaving actions length check") allowed the total sw flow actions
stream to grow beyond 64 KiB, which is valid, but also removed the last
guard preventing a generated nested action attribute from exceeding
U16 MAX.
An oversized generated container can thus be closed with a truncated
nla len. A later dump or teardown then walks a structurally different
stream than the one that was validated. In particular, an oversized
nested CLONE/CT action may cause subsequent bytes in the generated
stream to be interpreted as independent actions.
Keep the larger total-action-stream behavior, but make nested action
close reject generated containers that do not fit in nla len, and return
the error through all callers. For recursive SAMPLE, CLONE, DEC TTL, and
CHECK PKT LEN builders, trim resource-owning action-list tails in reverse
construction order before discarding failed wrappers, so resources copied
into the rejected tails are released before the wrappers are removed.
Most failed outer wrappers are discarded by truncating actions len after
child resources have been released. CHECK PKT LEN also trims its parent
after branch resources are gone. SET/TUNNEL close failures unwind their
known tun dst ownership directly, and SET TO MASKED has no external
ownership and truncates on close failure.
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Related Identifiers
Affected Products
Linux