| Title | Open5GS 2.7.7 Crash / Denial of Service |
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| Description | A crafted PFCP message sequence can crash the Open5GS UPF.
The issue is caused by incomplete handling of a failed GTP-U peer setup triggered through malformed Outer Header Creation data. In Open5GS v2.7.7, the failed setup path can leave a partially initialized GTP-U node in the peer list with an invalid address family. A subsequent PFCP request can reuse this stale state and reach PFCP processing that aborts with:
[pfcp] FATAL: Unknown family(0)
The issue is state-dependent because malformed PFCP processing first leaves invalid runtime state that is later reused by another request.
A successful trigger terminates the UPF process and disrupts the user-plane sessions handled by that UPF.
The vulnerability is reachable by a host that can access the PFCP/N4 interface on UDP port 8805. PFCP does not provide protocol-layer authentication, although N4 is normally deployed on a protected network.
The issue was reported to the Open5GS maintainers as GitHub issue #4699. The maintainers classified it as Type:Security and created a corrective commit explicitly referencing the issue. |
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| Source | ⚠️ https://github.com/open5gs/open5gs/issues/4699 |
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| User | ea1809 (UID 100625) |
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| Submission | 08/17/2026 11:43 (29 days ago) |
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| Moderation | 09/15/2026 11:10 (29 days later) |
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| Status | Accepted |
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| VulDB entry | 404086 [Open5GS up to 2.7.7 PFCP Message lib/pfcp/handler.c denial of service] |
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| Points | 20 |
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