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.
TridentStack Control tracks known vulnerabilities across your Windows, macOS, and Linux fleet and shows the fix as soon as one is published. See how it works
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-2026-53913 | Critical | 9.8 | 1.1% | - | Fix |
Common questions
How do I fix CVE-2026-40249?
No published fix for CVE-2026-40249 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-40249 being actively exploited?
Not that we know of. CVE-2026-40249 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.32% is the estimated probability that it will be exploited in the next 30 days. That is higher than 24% of all scored CVEs.
How severe is CVE-2026-40249?
CVE-2026-40249 has a CVSS v3 base score of 5.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
Embed a live status badge for CVE-2026-40249
Markdown
[](https://tridentstack.com/cve/CVE-2026-40249)HTML
<a href="https://tridentstack.com/cve/CVE-2026-40249"><img src="https://tridentstack.com/cve/badge/CVE-2026-40249.svg" alt="CVE-2026-40249"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
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.