Unauthenticated topology deletion via nil UPF dereference
Published May 27, 2026 · Updated May 27, 2026
Missing authentication in free5GC before 4.2.2 allows remote attackers to delete SMF topology entries through its UPI interface. The SMF DELETE /upi/v1/upNodesLinks/{upNodeRef} handler removes the named AN node before it unconditionally calls CancelAssociation through the node's absent UPF object, producing a nil-pointer panic. Network access to the SMF service-based interface is sufficient; Gin recovers the handler, but the in-memory topology deletion remains and disrupts later path selection.
Summary
What happened
Missing authentication in free5GC before 4.2.2 allows remote attackers to delete SMF topology entries through its UPI interface. The SMF DELETE /upi/v1/upNodesLinks/{upNodeRef} handler removes the named AN node before it unconditionally calls CancelAssociation through the node's absent UPF object, producing a nil-pointer panic. Network access to the SMF service-based interface is sufficient; Gin recovers the handler, but the in-memory topology deletion remains and disrupts later path selection.
The record
- CVE
- CVE-2026-44328
- Published
- May 27, 2026
- Updated
- May 27, 2026
- Vendor
- free5GC
- Product
- free5GC
- Classifications
- CWE-862, CWE-476, CWE-306, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 27, 2026CVE publishedPublication date reported by the CVE source.
- May 27, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 4.2.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GHSA-p9mg-74mg-cwwr SMF UPI DELETE proof of conceptfunctional · demonstrated
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Technologies
Your stack
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Your stack
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