CVE Catalog

CVE-2026-52915

HighCVSS 7.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.13%

3th percentile - higher than 3% of all known CVEs

Summary

In the Linux kernel, the netfilter ip6t_hbh module lacks validation of the Hop-by-Hop options list size. Userspace can supply an optsnr value larger than allowed (IP6T_OPTS_OPTSNR = 16), causing an out-of-bounds access on the opts array. The issue was reported by UBSAN as an array-index-out-of-bounds error.

Risk Assessment

An attacker with privileges to configure firewall rules (e.g., via nftables/iptables) could trigger a kernel panic or potentially escalate privileges by exploiting the out-of-bounds array access.

Recommendation

Immediately update the Linux kernel to a version that includes the fix validating optsnr in hbh_mt6_check(). If an update is not possible, restrict firewall rule configuration access to trusted users only.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: netfilter: ip6t_hbh: reject oversized option lists struct ip6t_opts stores at most IP6T_OPTS_OPTSNR option descriptors, but hbh_mt6_check() does not reject larger optsnr values supplied from userspace. Validate optsnr in the rule setup path so only match data that fits the fixed-size opts array can be installed. This follows the existing xtables pattern of rejecting invalid user-provided counts in checkentry() and keeps the packet matching path unchanged. `struct ip6t_opts` has a fixed `opts[IP6T_OPTS_OPTSNR]` array, where `IP6T_OPTS_OPTSNR` is 16, then off-by-one array access is possible: [ 137.924693][ T8692] UBSAN: array-index-out-of-bounds in ../net/ipv6/netfilter/ip6t_hbh.c:110:29 [ 137.926167][ T8692] index 16 is out of range for type '__u16 [16]'

Vulnerability data from NVD (NIST) · CISA KEV · EPSS