Description
In the Linux kernel, the following vulnerability has been resolved: ipvs: revalidate ihl to prevent out-of-bounds access While the outer IP header is already pulled into the skb head, we must be careful and revalidate the embedded headers after reading them from the skb frags to prevent out-of-bounds access. One such place reported by Sashiko is ip_vs_nat_icmp() where local process can change the ihl field and after skb_ensure_writable() we can see larger value which is a problem for the ip_send_check(cih) calls. Add check to drop the packet if the ihl field is changed.
References6
- git.kernel.org/stable/c/041b2303c8019394735c1f76c5138657bf660a7d
- git.kernel.org/stable/c/2512289cbf58706fd558e8fccea4e28003a2af54
- git.kernel.org/stable/c/5365f012451fce2453f13a568dcb72ea534c1e4d
- git.kernel.org/stable/c/d93660df4dd1d116f608ada4a29a80a5d6f0a6ed
- git.kernel.org/stable/c/eb81c8e758f49e04391f77d9470a6232bb5f1c7a
- git.kernel.org/stable/c/f55bb94946fb8ee6304590a731c39c1fbc3b28bc
Metrics
- CVSS 3.1
-
7.8
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 0% percentile: 3 · as of 9 November 2026
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.