CVE-2026-5265 Ovn: ovn: heap over-read in icmp error response generation
A malicious VM can trigger an ICMP error response that causes ovn-controller to leak heap memory contents back to the attacker.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-5265?
CVE-2026-5265 is a medium-severity vulnerability in Red Hat Fast Datapath for RHEL 7, published on 24 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
When generating an ICMP Destination Unreachable or Packet Too Big response, the handler copies a portion of the original packet into the ICMP error body using the IP header's self-declared total length (ip_tot_len for IPv4, ip6_plen for IPv6) without validating it against the actual packet buffer size. A VM can send a short packet with an inflated IP length field that triggers an ICMP error (e.g., by hitting a reject ACL), causing ovn-controller to read heap memory beyond the valid packet data and include it in the ICMP response sent back to the VM.
Weakness: CWE-130
Which versions are affected by CVE-2026-5265?
How do I fix CVE-2026-5265?
Apply the vendor's patch.
Is CVE-2026-5265 being exploited?
There is no known exploitation of CVE-2026-5265 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-5265, GHSA-whr7-6788-jg2p, UBUNTU-CVE-2026-5265.