CVE-2026-40249
MEDIUMDescription
free5GC is an open-source implementation of the 5G core network. In versions 4.2.1 and below of the UDR service, the PUT handler for updating Policy Data notification subscriptions at /nudr-dr/v2/policy-data/subs-to-notify/{subsId} does not return after request body retrieval or deserialization errors. Although HTTP 500 or 400 error responses are sent, execution continues and the processor is invoked with a potentially uninitialized or partially initialized PolicyDataSubscription object. This fail-open behavior may allow unintended modification of existing Policy Data notification subscriptions with invalid or empty input, depending on downstream processor and storage behavior. A patched version was not available at the time of publication.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 24% of all known CVEs.
References
Related Vulnerabilities
Other CWE-636 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-43532 | High | 8.8 | 12% | - | Fix |
| CVE-2023-28840 | High | 7.5 | 2.7% | - | Fix |
| CVE-2021-1578 | High | 8.8 | 2.0% | - | - |
| CVE-2023-28842 | Medium | 6.8 | 1.4% | - | Fix |
| CVE-2025-21210 | Medium | 4.2 | 1.1% | - | Fix |
| CVE-2024-3729 | Critical | 9.8 | 0.8% | - | Fix |
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-21.