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CVE-2026-33065

free5GC UDM incorrectly returns 500 for empty supi path parameter in DELETE sdm-subscriptions request

Also known asGHSA-958m-gxmc-mccmGO-2026-4758
Published
Mar 20, 2026
Updated
Apr 2, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk20th percentile+0.23%
0.00%0.26%0.52%0.78%0.0%0.0%0.0%0.3%Apr 26Jun 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected
🐹github.com/free5gc/udm

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. In versions prior to 1.4.2, the UDM incorrectly converts a downstream 400 Bad Request (from UDR) into a 500 Internal Server Error when handling DELETE requests with an empty supi path parameter. This leaks internal error handling behavior and makes it difficult for clients to distinguish between client-side errors and server-side failures. When a client sends a DELETE request with an empty supi (e.g., double slashes // in URL path), the UDM forwards the malformed request to UDR, which correctly returns 400. However, UDM propagates this as 500 SYSTEM_FAILURE instead of returning the appropriate 400 error to the client. This violates REST API best practices for DELETE operations. The issue has been patched in version 1.4.2.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/free5gc/udmall versions1.4.2

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/free5gc/udm. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update github.com/free5gc/udm to 1.4.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33065 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether CVE-2026-33065 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-33065. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. In versions prior to 1.4.2, the UDM incorrectly converts a downstream 400 Bad Request (from UDR) into a 500 Internal Server Error when handling DELETE requests with an empty supi path parameter. This leaks internal error handling behavior and makes it difficult for clients to distinguish between client-side errors and server-side failures. When a client sends a DELETE request with an empty supi (e.g., double slashes // in URL path), the UDM forwards the malformed request to UDR, which correctly ret
O3 Security · Impact-Aware SCA

Is CVE-2026-33065 in your dependencies?

O3 detects CVE-2026-33065 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.