netfilter: ip6t_hbh: reject oversized option lists

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EUVD-2026-38718

In the Linux kernel, the following vulnerability has been resolved: netfilter: ip6thbh: reject oversized option lists struct ip6topts stores at most IP6TOPTSOPTSNR option descriptors, but hbhmt6check does not reject larger optsnr values supplied from userspace. Validate optsnr in the rule setup...

CVE-2026-52915

CVE-2026-52915 concerns the Linux kernel netfilter ip6t_hbh module, where ip6t_opts may store at most IP6T_OPTS_OPTSNR (16) option descriptors but hbh_mt6_check() did not reject larger optsnr values from userspace. This allowed a potential out-of-bounds condition (UBSAN: array-index-out-of-bounds...