CVE-2026-52999
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.58%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- EPSS
- 0.58% probability · 46th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-125
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/0145548346c4a30981a870a8ca00eac46ba27e85Patch
- https://git.kernel.org/stable/c/1c136f2c44a5913646bac85303612fd0825197a0Patch
- https://git.kernel.org/stable/c/1e19a07291bb8682c14c39a64725a3ae54ab8cccPatch
- https://git.kernel.org/stable/c/21883587593d7c8bb519a79460a0b5bc5ffbdabdPatch
- https://git.kernel.org/stable/c/32e50f92c7cf3f4eba29622179a5fcdc2aebab41Patch
- https://git.kernel.org/stable/c/70a3f31d25cf2ec9d4ddfa408120171ead955623Patch
- https://git.kernel.org/stable/c/edb78a142d2e5948e63647c0646aa7e7886935f0Patch
- https://git.kernel.org/stable/c/f5ca450087c3baf3651055e7a6de92600f827af3Patch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.