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CVE-2026-74669: ipvs: clear IPv4 options after rebasing tunnel ICMP errors

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-22 · updated 2026-10-16

Description

In the Linux kernel, the following vulnerability has been resolved: ipvs: clear IPv4 options after rebasing tunnel ICMP errors ip_vs_in_icmp() rebases an skb from the outer ICMP packet to the quoted original request before passing it to icmp_send(). However, IPCB(skb)->opt still describes the outer IPv4 header. A timestamp option in the outer header can therefore leave an offset that points into the quoted transport header after the rebase. __ip_options_echo() treats a byte at that stale location as the option length and copies it into the fixed-size option storage on the __icmp_send() stack, causing a stack out-of-bounds write. Clear the stale option metadata after resetting the network header. Keep the remaining control block fields, including the ingress interface used by the ICMP response path.

Affected products

• Linux kernel: 3.7 — 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/37c61b3745129cbd682c557b51345828120972e5
• https://git.kernel.org/stable/c/384b4dae14277d369221d187e9b3af56c79d2e50
• https://git.kernel.org/stable/c/6f46fc460e9316062bdcdf89199eb5d7a33da33b
• https://git.kernel.org/stable/c/75eec935444db4af2123e0491936f6e273d7ea00
• https://git.kernel.org/stable/c/79ffa99202c944467e28b13b513bf2998732edff
• https://git.kernel.org/stable/c/c9413b50204738fbc429bb86bf01353c393a6c28
• https://git.kernel.org/stable/c/e0ba936287dfe9783426aac27e5fd76fe35b38c9
• https://git.kernel.org/stable/c/ed246dd85ebf27c1f6b7897834d40786c0ca3006

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