Unauthenticated UDM crash via missing UE-context validation
Published Mar 20, 2026 · Updated Mar 20, 2026
NULL pointer dereference in free5GC UDM before 1.4.2 allows remote attackers to crash the service through a crafted callback POST request. DataChangeNotificationProcedure discards the success flag from UdmUeFindBySupi and subsequently uses the missing UE context; the HTTP route also omits the required SUPI segment. An unauthenticated request to the UDM HTTP callback endpoint is sufficient, interrupting all UDM functions until the process is restarted.
Summary
What happened
NULL pointer dereference in free5GC UDM before 1.4.2 allows remote attackers to crash the service through a crafted callback POST request. DataChangeNotificationProcedure discards the success flag from UdmUeFindBySupi and subsequently uses the missing UE context; the HTTP route also omits the required SUPI segment. An unauthenticated request to the UDM HTTP callback endpoint is sufficient, interrupting all UDM functions until the process is restarted.
The record
- CVE
- CVE-2026-33064
- Published
- Mar 20, 2026
- Updated
- Mar 20, 2026
- Vendor
- free5GC
- Product
- free5GC
- Classifications
- CWE-476, CWE-478, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 20, 2026CVE publishedPublication date reported by the CVE source.
- Mar 20, 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=< 1.4.2
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
- Crafted sdm-subscriptions POST proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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