CVE-2026-1739
Published: 02 February 2026
Summary
CVE-2026-1739 is a medium-severity Improper Resource Shutdown or Release (CWE-404) vulnerability in Free5Gc Pcf. Its CVSS base score is 5.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 16.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and SC-24 (Fail in Known State).
Deeper analysis
CVE-2026-1739 is a null pointer dereference vulnerability in the Free5GC Policy Control Function (PCF) component, affecting versions up to 1.4.1. The issue resides in the HandleCreateSmPolicyRequest function within the file internal/sbi/processor/smpolicy.go. It is classified under CWE-404 (Improper Resource Shutdown or Release) and CWE-476 (NULL Pointer Dereference), with a CVSS v3.1 base score of 5.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L), indicating medium severity primarily impacting availability.
An unauthenticated remote attacker can exploit this vulnerability by manipulating the HandleCreateSmPolicyRequest function, leading to a denial-of-service condition through a crash caused by the null pointer dereference. The attack requires low complexity, no user interaction, and no privileges, making it feasible over the network without changing the scope of impact.
Mitigation is available via a patch identified by the commit hash df535f5524314620715e842baf9723efbeb481a7, accessible through the Free5GC PCF GitHub repository. Applying this patch is the recommended fix, as detailed in related GitHub issues #803 and pull request #62. The exploit has been publicly disclosed and may be usable by attackers.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-5125
Vulnerability details
A vulnerability has been found in Free5GC pcf up to 1.4.1. This affects the function HandleCreateSmPolicyRequest of the file internal/sbi/processor/smpolicy.go. The manipulation leads to null pointer dereference. The attack is possible to be carried out remotely. The exploit has been…
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disclosed to the public and may be used. The identifier of the patch is df535f5524314620715e842baf9723efbeb481a7. Applying a patch is the recommended action to fix this issue.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Null dereference in exposed PCF SBI handler directly enables remote unauthenticated exploitation of a public-facing 5G network function (T1190) resulting in application crash and DoS (T1499.004).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires timely application of the vendor patch (commit df535f55243) that eliminates the null-pointer dereference in HandleCreateSmPolicyRequest.
Mandates validation of SM policy request inputs before they reach the vulnerable code path, preventing malformed data from triggering the dereference.
Requires the PCF to fail in a known, non-crashing state when an unexpected null is encountered, limiting the availability impact of the DoS.