PT-2026-51893 · Linux · Linux
Published
2026-06-24
·
Updated
2026-06-24
·
CVE-2026-52999
None
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In the Linux kernel, the following vulnerability has been resolved:
netfilter: nfnetlink osf: fix out-of-bounds read on option matching
In nf osf match(), the nf osf hdr ctx structure is initialized once
and passed by reference to nf osf match one() for each fingerprint
checked. During TCP option parsing, nf osf match one() advances the
shared ctx->optp pointer.
If a fingerprint perfectly matches, the function returns early without
restoring ctx->optp to its initial state. If the user has configured
NF OSF LOGLEVEL ALL, the loop continues to the next fingerprint.
However, because ctx->optp was not restored, the next call to
nf osf match one() starts parsing from the end of the options buffer.
This causes subsequent matches to read garbage data and fail
immediately, making it impossible to log more than one match or logging
incorrect matches.
Instead of using a shared ctx->optp pointer, pass the context as a
constant pointer and use a local pointer (optp) for TCP option
traversal. This makes nf osf match one() strictly stateless from the
caller's perspective, ensuring every fingerprint check starts at the
correct option offset.
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Related Identifiers
Affected Products
Linux