What’s Vulnerable › Vulnerabilities

CVE-2026-72348: netfilter: ip6tables: mark malformed IPv6 extension headers for hotdrop

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-15 · updated 2026-10-16

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: ip6tables: mark malformed IPv6 extension headers for hotdrop The ah, hbh and rt matches check that the fixed extension header is present, then use the header length field to derive the advertised extension header length for matching. For the ah match, add the missing advertised-length check. For hbh and rt, update the existing advertised-length checks. In all three cases, set hotdrop to true before returning false when the advertised extension header length exceeds the available skb data. Returning false treats the packet as a rule mismatch. Set hotdrop to true and drop malformed packets so they cannot bypass rules intended to drop packets with these IPv6 extension headers.

Affected products

• Linux kernel: 2.6.12 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux kernel 7.2. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/2fd89a50a9783eed8ed23866b11c8b3d8779a7a8
• https://git.kernel.org/stable/c/3578b6d92a5b1e603ae6e8c8f5538a709f03aba4
• https://git.kernel.org/stable/c/3d441be2b1c5e98167302fa1c7b61960a067b112
• https://git.kernel.org/stable/c/43ccc20b5a733226417832cf16ef45322e594990
• https://git.kernel.org/stable/c/d5e39e5eb6b30bc4a3bb7aba54c293cf36a806c7
• https://git.kernel.org/stable/c/f16d856b6af5fd0e7cb0b0212f70825b599ef72e
• https://git.kernel.org/stable/c/f775fcf384b06f35b612f78fa5601fee99eb6513
• https://git.kernel.org/stable/c/fc416870100cf16d5b9495199355a679c3a02d48

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