CVE-2025-0650 – This vulnerability in Open Virtual Network (OVN... (How to Fix)

Q: What is the severity of CVE-2025-0650?

CVE-2025-0650 has a CVSS score of 8.1 (HIGH). This vulnerability in Open Virtual Network (OVN) allows specially crafted UDP packets to bypass egress access control lists (ACLs), potentially enabling unauthorized access to virtual machines and containers. It affects OVN installations configured with logical switches that have DNS records and egress ACLs, posing a risk to cloud and virtualized environments using OVN for network management.

📋 TL;DR

This vulnerability in Open Virtual Network (OVN) allows specially crafted UDP packets to bypass egress access control lists (ACLs), potentially enabling unauthorized access to virtual machines and containers. It affects OVN installations configured with logical switches that have DNS records and egress ACLs, posing a risk to cloud and virtualized environments using OVN for network management.

💻 Affected Systems

Products:

Open Virtual Network (OVN)

Versions: Specific versions not detailed in references; check Red Hat advisories for exact ranges.

Operating Systems: Linux-based systems running OVN, particularly Red Hat Enterprise Linux and related distributions

Default Config Vulnerable: ✅ No

Notes: Only affects configurations with logical switches that have DNS records set and egress ACLs configured.

⚠️ Manual Verification Required

This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.

Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).

🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.

Recommended Actions:

Review the CVE details at NVD
Check vendor security advisories for your specific version
Test if the vulnerability is exploitable in your environment
Consider updating to the latest version as a precaution

⚠️ Risk & Real-World Impact

🔴

Worst Case

Attackers could gain unauthorized access to sensitive virtual machines or containers, leading to data theft, lateral movement, or disruption of services.

🟠

Likely Case

Unauthorized network traffic bypassing egress controls, potentially allowing data exfiltration or communication with malicious external servers.

🟢

If Mitigated

If proper network segmentation and monitoring are in place, impact may be limited to isolated segments with minimal data exposure.

🌐 Internet-Facing: MEDIUM, as exploitation requires access to the OVN network, but if exposed, it could allow bypass of egress controls from internet-facing systems.

🏢 Internal Only: HIGH, as internal attackers or compromised systems could exploit this to bypass egress ACLs and access restricted resources.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires crafting UDP packets and knowledge of the OVN network configuration, making it moderately complex.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check Red Hat advisories (e.g., RHSA-2025:1083 to RHSA-2025:1087) for specific patched versions.

Vendor Advisory: https://access.redhat.com/errata/RHSA-2025:1083

Restart Required: No

Instructions:

1. Identify affected OVN installations. 2. Apply the relevant Red Hat patch via yum update or similar package manager. 3. Verify the patch is applied and restart OVN services if necessary.

🔧 Temporary Workarounds

Disable DNS records on logical switches

all

Remove DNS records from logical switches with egress ACLs to mitigate the bypass vulnerability.

ovn-nbctl remove logical_switch <switch_name> dns_records <record>

🧯 If You Can't Patch

Implement strict network monitoring and intrusion detection to alert on suspicious UDP traffic bypassing egress ACLs.
Enhance network segmentation to limit the blast radius and reduce exposure of sensitive systems.

🔍 How to Verify

Check if Vulnerable:

Check OVN configuration for logical switches with DNS records and egress ACLs; review version against Red Hat advisories.

Check Version:

ovn-nbctl --version

Verify Fix Applied:

After patching, verify the OVN version is updated and test egress ACL functionality with UDP packets.

📡 Detection & Monitoring

Log Indicators:

Unexpected UDP traffic logs in OVN or system logs indicating ACL bypass attempts.

Network Indicators:

Anomalous UDP packets targeting logical switches with DNS records, especially if they bypass egress rules.

SIEM Query:

Example: search for UDP traffic from internal sources to external IPs where egress ACLs are configured but bypassed.

📊 Metadata

CVE ID: CVE-2025-0650

CVSS v3 Score: 8.1 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE: CWE-284

EPSS Score: 1.3% exploit probability (79.4th percentile)

Published: January 23, 2025

Last Updated: February 6, 2025

🔗 References

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