CVE-2026-43099 ipv4: icmp: fix null-ptr-deref in icmp_build_probe()
A null pointer dereference in the Linux kernel's ICMP probe handling can cause a system crash when IPv6 is disabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43099?
CVE-2026-43099 is a high-severity vulnerability in Linux kernel, published on 6 May 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:
ipv4: icmp: fix null-ptr-deref in icmp_build_probe()
ipv6_stub->ipv6_dev_find() may return ERR_PTR(-EAFNOSUPPORT) when the IPv6 stack is not active (CONFIG_IPV6=m and not loaded), and passing this error pointer to dev_hold() will cause a kernel crash with null-ptr-deref.
Instead, silently discard the request. RFC 8335 does not appear to define a specific response for the case where an IPv6 interface identifier is syntactically valid but the implementation cannot perform the lookup at runtime, and silently dropping the request may safer than misreporting "No Such Interface".
Weakness: CWE-476
Which versions are affected by CVE-2026-43099?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43099?
Apply the vendor's patch.
Is CVE-2026-43099 being exploited?
There is no known exploitation of CVE-2026-43099 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43099, DEBIAN-CVE-2026-43099, GHSA-vp8v-gjj6-f34x, ROOT-OS-DEBIAN-12-CVE-2026-43099, ROOT-OS-UBUNTU-2204-CVE-2026-43099, ROOT-OS-UBUNTU-2404-CVE-2026-43099 and 1 more.