CVE-2026-52915 netfilter: ip6t_hbh: reject oversized option lists
A missing bounds check in the Linux kernel netfilter module allows an attacker to trigger an out-of-bounds array access, potentially causing a crash or code execution.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-52915?
CVE-2026-52915 is a high-severity vulnerability in Linux kernel, published on 24 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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]'
Which versions are affected by CVE-2026-52915?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-52915?
Apply the vendor's patch.
Is CVE-2026-52915 being exploited?
There is no known exploitation of CVE-2026-52915 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-90908, BELL-CVE-2026-52915, DEBIAN-CVE-2026-52915, GHSA-9hfh-p7qh-475c, ROOT-OS-DEBIAN-11-CVE-2026-52915, ROOT-OS-DEBIAN-12-CVE-2026-52915 and 3 more.