In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: ignore explicit helper on new expectations Use the existing master conntrack helper, anything else is not really supported and it just makes validation more complicated, so just ignore what helper userspace suggests for this expectation. This was uncovered when validating CTAEXPECTCLASS via different helper provided by userspace than the existing master conntrack helper: BUG: KASAN: slab-out-of-bounds in nfctexpectrelatedreport+0x2479/0x27c0 Read of size 4 at addr ffff8880043fe408 by task poc/102 Call Trace: nfctexpectrelatedreport+0x2479/0x27c0 ctnetlinkcreateexpect+0x22b/0x3b0 ctnetlinknewexpect+0x4bd/0x5c0 nfnetlinkrcvmsg+0x67a/0x950 netlinkrcvskb+0x120/0x350 Allowing to read kernel memory bytes off the expectation boundary. CTAEXPECTHELP_NAME is still used to offer the helper name to userspace via netlink dump.