CVE-2025-0650: Ovn: egress acls may be bypassed via specially crafted udp packet
A flaw was found in the Open Virtual Network (OVN). Specially crafted UDP packets may bypass egress access control lists (ACLs) in OVN installations configured with a logical switch with DNS records set on it and if the same switch has any egress ACLs configured. This issue can lead to unauthorized access to virtual machines and containers running on the OVN network.
Other sources
Multiple versions of OVN (Open Virtual Network) are vulnerable to allowing crafted UDP packets to bypass egress access control list (ACL) rules. This can result in unauthorized access to virtual machines and containers running on the OVN network.
OVN provides rudimentary DNS caching as an optional feature to speed up lookups of frequently-used domains. When this feature is enabled, due to the OpenFlow rules that OVN installs in Open vSwitch, it is possible for an attacker to craft a UDP packet that can bypass egress ACL rules. Egress ACL rules are those that have the "direction" set to "to-lport".
The OVN installation is vulnerable if a logical switch has DNS records set on it AND if the same switch has any egress ACLs configured on it. The switch is considered to have egress ACLs configured if the switch has an egress ACL configured directly on it using the "acls" column of the logical switch. A switch is also considered to have egress ACLs configured if any of its logical switch ports are part of a port group that has egress ACLs configured in its "acls" column.
We recommend that users of OVN apply the linked patches, or upgrade to a known patched version of OVN. These include:
v22.03.8 v24.03.5 v24.09.2
— Red Hat
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-0650?
CVE-2025-0650 has been classified as a potentially high severity vulnerability due to its ability to bypass egress access control lists.
How do I fix CVE-2025-0650?
To mitigate CVE-2025-0650, ensure that your OVN installation is upgraded to a version newer than 24.09.2 or patched accordingly.
What types of systems are affected by CVE-2025-0650?
CVE-2025-0650 affects Open Virtual Network installations with logical switches that have DNS records and configured egress ACLs.
What are the potential risks of CVE-2025-0650?
The potential risks of CVE-2025-0650 include unauthorized access to restricted network segments and potential data exfiltration.
Is there a public record of CVE-2025-0650?
Yes, CVE-2025-0650 has public documentation detailing its effects and mitigation strategies available through security advisories.