CVE-2026-74747

ipvs: revalidate ihl to prevent out-of-bounds access

State: Published
Severity: 7.8 High
Published: Aug 26, 2026
Updated: Oct 30, 2026
Reserved: Aug 15, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before f55bb94946fb8ee6304590a731c39c1fbc3b28bcAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 2512289cbf58706fd558e8fccea4e28003a2af54Affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 041b2303c8019394735c1f76c5138657bf660a7dAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before eb81c8e758f49e04391f77d9470a6232bb5f1c7aAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 5365f012451fce2453f13a568dcb72ea534c1e4dAffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before d93660df4dd1d116f608ada4a29a80a5d6f0a6edAffected
LinuxLinux	2.6.12Affected before 2.6.12Not affected 6.1.191 through 6.1.Not affected 6.6.160 through 6.6.Not affected 6.12.114 through 6.12.Not affected 6.18.57 through 6.18.Not affected 7.1.10 through 7.1.*Not affected 7.2 and laterNot affected

Product

Versions

LinuxLinux

1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before f55bb94946fb8ee6304590a731c39c1fbc3b28bcAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 2512289cbf58706fd558e8fccea4e28003a2af54Affected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 041b2303c8019394735c1f76c5138657bf660a7dAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before eb81c8e758f49e04391f77d9470a6232bb5f1c7aAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before 5365f012451fce2453f13a568dcb72ea534c1e4dAffected
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 to before d93660df4dd1d116f608ada4a29a80a5d6f0a6edAffected

LinuxLinux

2.6.12Affected
before 2.6.12Not affected
6.1.191 through 6.1.*Not affected
6.6.160 through 6.6.*Not affected
6.12.114 through 6.12.*Not affected
6.18.57 through 6.18.*Not affected
7.1.10 through 7.1.*Not affected
7.2 and laterNot affected

References

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