0.0
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CVE-2026-52999
netfilter: nfnetlink_osf: fix out-of-bounds read on option matching
Description

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.

INFO

Published Date :

June 24, 2026, 4:29 p.m.

Last Modified :

June 24, 2026, 4:29 p.m.

Remotely Exploit :

No

Source :

Linux
Affected Products

The following products are affected by CVE-2026-52999 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

Solution
Address out-of-bounds read by using a local pointer for TCP option traversal.
  • Modify nf_osf_match() to use a local pointer for parsing.
  • Ensure context pointer is restored after processing.
  • Apply the Linux kernel patch for netfilter.

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