CVE-2026-52999
Last modified
CVE-2026-52999 is a critical-severity vulnerability rated 9.1/10 on the CVSS scale. 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. EPSS estimates a 0.52% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 4.19.26, < 4.20 |
| Linux | Linux Kernel | >= 4.20.13, < 5.0 |
| Linux | Linux Kernel | >= 5.0.1, < 5.10.258 |
| Linux | Linux Kernel | >= 5.11, < 5.15.209 |
| Linux | Linux Kernel | >= 5.16, < 6.1.175 |
| Linux | Linux Kernel | >= 6.2, < 6.6.141 |
| Linux | Linux Kernel | >= 6.7, < 6.12.91 |
| Linux | Linux Kernel | >= 6.13, < 6.18.33 |
| Linux | Linux Kernel | >= 6.19, < 7.0.10 |
| Linux | Linux Kernel | 5.0 |
References
Timeline
- Published
- Last Modified
- Status
- Analyzed
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- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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