Oai-cn5g-amf: Authentication Bypass by Capture-replay
CVE-2026-30080 is a high-severity authentication bypass by capture-replay vulnerability in Oai-cn5g-amf from Openairinterface, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Oai-cn5g-amf versions: 2.2.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.26% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Oai-cn5g-amf you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Openairinterface | Oai-cn5g-amf | 2.2.0 | Not stated |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by CISA (ADP).
Official description
OpenAirInterface v2.2.0 accepts Security Mode Complete without any integrity protection. Configuration has supported integrity NIA1 and NIA2. But if an UE sends initial registration request with only security capability IA0, OpenAirInterface accepts and proceeds. This downgrade security context can lead to the possibility of replay attack.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass by Capture-replay
A capture-replay flaw exists when the design of the product makes it possible for a malicious user to sniff network traffic and bypass authentication by replaying it to the server in question to the same effect as the original message (or with minor changes).
How developers prevent this class of flaw
- Utilize some sequence or time stamping functionality along with a checksum which takes this into account in order to ensure that messages can be parsed only once.
- Since any attacker who can listen to traffic can see sequence numbers, it is necessary to sign messages with some kind of cryptography to ensure that sequence numbers are not simply doctored along with content.
More Authentication Bypass by Capture-replay vulnerabilities (CWE-294)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Technical write-ups (may include proof of concept)
- gitlab.eurecom.fr/oai/cn5g/oai-cn5g-amf/-/issues/78Exploit, Issue Tracking, Third Party Advisory
Other vulnerabilities in Oai-cn5g-amf
- 7.5 High severity
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Authentication Bypass by Capture-replay vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 8.3 High severity
- 9.8 Critical severity
- 7.5 High severity
- 8.0 High severity
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