CVE-2026-46266: inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-03 · updated 2026-10-19
Weakness: CWE-20

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.

Affected products

Linux kernel: from 2.6.12.1 before 6.6.128; from 6.7 before 6.12.75; from 6.13 before 6.18.14; from 6.19 before 6.19.4; 2.6.12, 2.6.12-rc2, 2.6.12-rc3, 2.6.12-rc4, 2.6.12-rc5 — fixed in 6.12.75, 6.18.14, 6.19.4, 6.6.128

How to fix

Upgrade to a fixed version: Linux kernel 6.12.75, 6.18.14, 6.19.4, 6.6.128. Check the vendor advisory for mitigations.

References

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