Is there a public PoC exploit available for CVE-2026-7781?

Yes, a public proof-of-concept exploit is available for CVE-2026-7781. Prioritise patching immediately. EPSS: 0.0%.

Open5GS CVE-2026-7781

Q: What is the CVSS score of CVE-2026-7781?

CVE-2026-7781 has a CVSS 4.0 base score of 2.1 (Low). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

EUVD-2026-27151 LOW

Improper Resource Shutdown or Release (CWE-404)

2026-05-04 VulDB

Denial Of Service Open5gs

2.1

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

2.1 LOW

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

May 04, 2026 - 23:30 vuln.today

Severity Changed

May 04, 2026 - 23:22 NVD

MEDIUM LOW

CVSS changed

May 04, 2026 - 23:22 NVD

4.3 (MEDIUM) 2.1 (LOW)

DescriptionCVE.org

A security vulnerability has been detected in Open5GS up to 2.7.7. Affected by this issue is the function udm_nudm_uecm_handle_amf_registration_update of the file /src/udm/nudm-handler.c of the component amf-3gpp-access Endpoint. The manipulation leads to denial of service. The attack is possible to be carried out remotely. The exploit has been disclosed publicly and may be used. The project was informed of the problem early through an issue report but has not responded yet.

AnalysisAI

Denial of service in Open5GS up to version 2.7.7 affects the AMF 3GPP access endpoint handler (udm_nudm_uecm_handle_amf_registration_update function), allowing authenticated remote attackers to crash the UDM service via malformed registration update messages. Publicly available exploit code exists, and the vendor was notified early but has not released a patch as of the analysis date.

Technical ContextAI

Open5GS is an open-source implementation of 5G network core functions. The vulnerability exists in the User Data Management (UDM) component's NUDM (Namf_NUDM) handler, specifically in the function responsible for processing AMF 3GPP access registration updates from the Access and Mobility Function (AMF). The affected code path processes incoming HTTP requests to the /nudm-uecm endpoint. CWE-404 (Improper Resource Validation) indicates that the function does not properly validate or handle incoming registration update messages, leading to a condition where the service crashes. The vulnerability affects versions up to and including 2.7.7 as indicated by the CPE string cpe:2.3:a:n/a:open5gs:*:*:*:*:*:*:*:*.

RemediationAI

Primary remediation is to upgrade to a patched version once the vendor releases one; monitor GitHub releases at https://github.com/open5gs/open5gs/ for security updates. Until a patch is available, operators should implement network segmentation to restrict AMF-to-UDM communication to trusted sources only, using firewall rules to allow only known AMF IP addresses to reach the UDM service on port 80/443 (or the configured NUDM endpoint port). Additionally, disable or isolate the AMF 3GPP access endpoint if not required for your deployment. Monitor UDM service logs for crashes or errors in the nudm-handler component and implement automated service restart with health checks to minimize denial of service impact. If feasible, run Open5GS UDM in a containerized environment with resource limits and restart policies to automatically recover from crashes. These controls address availability impact but do not eliminate the underlying vulnerability and should be temporary measures pending vendor patch release.