CVE-2026-74747 ipvs: revalidate ihl to prevent out-of-bounds access
A local attacker can trigger an out-of-bounds access in the Linux kernel IPVS module by manipulating IP header fields, potentially causing a crash or information leak.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74747?
CVE-2026-74747 is a high-severity memory corruption vulnerability in Linux, published on 26 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ipvs: revalidate ihl to prevent out-of-bounds access
While the outer IP header is already pulled into the skb head, we must be careful and revalidate the embedded headers after reading them from the skb frags to prevent out-of-bounds access.
One such place reported by Sashiko is ip_vs_nat_icmp() where local process can change the ihl field and after skb_ensure_writable() we can see larger value which is a problem for the ip_send_check(cih) calls.
Add check to drop the packet if the ihl field is changed.
Which versions are affected by CVE-2026-74747?
How do I fix CVE-2026-74747?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-74747 being exploited?
There is no known exploitation of CVE-2026-74747 in the wild and no public exploit code.
Sources
Also known as AZL-97830, BELL-CVE-2026-74747, DEBIAN-CVE-2026-74747, GHSA-769p-7f5g-9f2g, UBUNTU-CVE-2026-74747.