CVE-2026-30077 Overview
A denial of service vulnerability exists in OpenAirInterface V2.2.0 where the Access and Mobility Management Function (AMF) crashes when it fails to decode certain malformed network messages. While not all decode failures result in a crash, the vulnerability produces consistent crashes for specific crafted inputs, making it reliably exploitable by attackers with network access.
Critical Impact
An unauthenticated remote attacker can crash the AMF component of OpenAirInterface 5G core network by sending specially crafted packets, causing denial of service to mobile network operations.
Affected Products
- OpenAirInterface V2.2.0
- OpenAirInterface OAI-CN5G-AMF component
- 5G Core Network deployments using vulnerable OAI versions
Discovery Timeline
- 2026-03-30 - CVE CVE-2026-30077 published to NVD
- 2026-04-01 - Last updated in NVD database
Technical Details for CVE-2026-30077
Vulnerability Analysis
This vulnerability is classified under CWE-20 (Improper Input Validation), affecting the message decoding functionality within the OpenAirInterface AMF component. The AMF is a critical 5G core network function responsible for access control, mobility management, and NAS (Non-Access Stratum) signaling.
The vulnerability stems from inadequate error handling during the message decoding process. When the AMF receives certain malformed protocol messages, the decode function fails to properly handle the error condition, resulting in an uncontrolled crash. The crash behavior is deterministic—the same malformed input will consistently trigger the same crash condition.
Root Cause
The root cause is improper input validation (CWE-20) in the message decoding pathway of the AMF component. When specific byte sequences are processed, the decoder encounters an error state that is not properly caught or handled, leading to a crash rather than graceful error recovery. The fix was addressed in Merge Request #414 which implements proper validation and error handling for these decode failures.
Attack Vector
The attack can be executed remotely over the network without requiring authentication or user interaction. An attacker with network access to the AMF interface can send crafted packets containing malformed message data.
The vulnerability can be triggered using a specific hex stream payload. An example malformed input that triggers the crash is documented as: 80 00 00 0E 00 00 01 00 0F 80 02 02 40 00 58 00 01 88. This payload, when decoded by the vulnerable AMF, results in a consistent crash. Additional technical details are available in the GitLab Issue #76.
Detection Methods for CVE-2026-30077
Indicators of Compromise
- Unexpected AMF process crashes or restarts in log files
- Network traffic containing malformed NAS or NGAP messages with unusual byte patterns
- Repeated crash dumps from the oai-cn5g-amf process with decode-related stack traces
- Abnormal increase in AMF service restart events
Detection Strategies
- Monitor AMF process stability and implement alerting on unexpected terminations
- Deploy network traffic analysis to detect malformed 5G signaling messages targeting the AMF interface
- Implement deep packet inspection rules to identify suspicious hex patterns matching known exploit payloads
- Review AMF debug logs for repeated decode failure messages followed by crashes
Monitoring Recommendations
- Enable verbose logging on the AMF component to capture decode error events
- Set up process monitoring with automatic alerting for AMF service crashes
- Implement network-level monitoring for anomalous traffic patterns on AMF-facing interfaces
- Establish baseline metrics for normal AMF restart frequency to detect exploitation attempts
How to Mitigate CVE-2026-30077
Immediate Actions Required
- Upgrade OpenAirInterface to a patched version that includes the fix from Merge Request #414
- Implement network segmentation to limit direct external access to the AMF component
- Deploy rate limiting on AMF interfaces to mitigate potential DoS impact
- Enable process restart policies to minimize service disruption from crashes
Patch Information
The vulnerability has been addressed by the OpenAirInterface development team. The fix is available in Merge Request #414 on the Eurecom GitLab repository. Organizations should update to the latest version of oai-cn5g-amf that includes this merge request to remediate the vulnerability.
Workarounds
- Deploy network firewalls or IPS rules to filter potentially malicious packets before they reach the AMF
- Implement robust process supervision with automatic restart capabilities to minimize downtime
- Use network access controls to restrict which entities can send traffic to the AMF interface
- Consider deploying a proxy or filtering layer in front of the AMF to validate incoming messages
# Configuration example - Process supervision for AMF
# Restart policy for containerized deployments
# Add to docker-compose.yml or Kubernetes deployment
restart: always
# Or for systemd-managed services:
# systemctl edit oai-amf.service
# [Service]
# Restart=always
# RestartSec=5
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
