CVE-2026-46266 inet: RAW sockets using IPPROTO_RAW MUST drop incoming ICMP
A malicious ICMP packet can corrupt the FNHE cache via IPPROTO_RAW sockets, causing a denial of service in the Linux kernel.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46266?
CVE-2026-46266 is a critical denial of service vulnerability in Linux kernel, published on 3 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-20
Which versions are affected by CVE-2026-46266?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46266?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-46266 being exploited?
There is no known exploitation of CVE-2026-46266 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-46266, DEBIAN-CVE-2026-46266, GHSA-3vgg-pc24-vv5m, ROOT-OS-DEBIAN-11-CVE-2026-46266, ROOT-OS-DEBIAN-12-CVE-2026-46266, ROOT-OS-UBUNTU-2204-CVE-2026-46266 and 2 more.