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CVE-2026-53551

Published Jul 31, 2026 CWE-20 EPSS 0.43% (36th pctl)

Overview

CVE-2026-53551 is a known-severity vulnerability. It was published on July 31, 2026.

Technical Description

free5GC is an open-source implementation of the 5G core network. Prior to 1.4.5, the free5GC AUSF (Authentication Server Function) does not validate the supiOrSuci field in UE authentication requests. Null bytes (\x00) and other control characters pass through JSON parsing unchanged and are forwarded to the UDM in an unescaped URL path. This causes Go's net/url.Parse() to fail, returning HTTP 500 "System failure" and leaking internal stack traces. An unauthenticated attacker can trigger this at scale causing denial of service for all subscribers attempting authentication through the affected AUSF. This vulnerability is fixed in 1.4.5.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHub github.com/free5gc/ausf/commit/bfc4a10094dbacbd862baa4686829f3fcc06ce1e GitHub github.com/free5gc/ausf/pull/61 GitHub github.com/free5gc/ausf/releases/tag/v1.4.5 GitHub github.com/free5gc/free5gc/issues/1048 GitHub github.com/free5gc/free5gc/releases/tag/v4.2.2 GitHub github.com/free5gc/free5gc/security/advisories/GHSA-qj55-47fp-p62j GitHub github.com/free5gc/free5gc/security/advisories/GHSA-qj55-47fp-p62j

Frequently Asked Questions

What is CVE-2026-53551?

CVE-2026-53551 is a known-severity vulnerability. It was published on July 31, 2026.

How severe is CVE-2026-53551?

CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.

How do I fix or remediate CVE-2026-53551?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-53551?

CyberStrike's AI-powered security agents can automatically detect CVE-2026-53551 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.

How CyberStrike Helps

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HackBrowser

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