Description
The free5GC UPF suffers from a lack of bounds checking on the SEID when processing PFCP Session Deletion Requests. An unauthenticated remote attacker can send a request with a very large SEID (e.g., 0xFFFFFFFFFFFFFFFF) that causes an integer conversion/underflow in LocalNode.DeleteSess() / LocalNode.Sess() when a uint64 SEID is converted to int and used in index arithmetic. This leads to a negative index into n.sess and a Go runtime panic, resulting in a denial of service (UPF crash). The issue has been reproduced on free5GC v4.1.0 with crashes observed in the session lookup/deletion path in internal/pfcp/node.go; other versions may also be affected. No authentication is required.
CVSS Metrics
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack Vector
- network
- Complexity
- low
- Privileges
- none
- User Action
- none
- Scope
- unchanged
- Confidentiality
- none
- Integrity
- none
- Availability
- high
- Weaknesses
- CWE-129
Metadata
- Primary Vendor
- FREE5GC
- Published
- 12/18/2025
- Last Modified
- 1/7/2026
- Source
- NIST NVD
- Note: Verify all details with official vendor sources before applying patches.
Affected Products
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