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Description

Free5GC is an open-source Linux Foundation project for 5th generation (5G) mobile core networks. Versions prior to 1.4.2 are vulnerable to null byte injection in URL path parameters. A remote attacker can inject null bytes (URL-encoded as %00) into the supi path parameter of the UDM's Nudm_SubscriberDataManagement API. This causes URL parsing failure in Go's net/url package with the error "invalid control character in URL", resulting in a 500 Internal Server Error. This null byte injection vulnerability can be exploited for denial of service attacks. When the supi parameter contains null characters, the UDM attempts to construct a URL for UDR that includes these control characters. Go's URL parser rejects them, causing the request to fail with 500 instead of properly validating input and returning 400 Bad Request. This issue has been fixed in version 1.4.2.

PUBLISHED Reserved 2026-03-17 | Published 2026-03-20 | Updated 2026-03-20 | Assigner GitHub_M




HIGH: 8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Problem types

CWE-158: Improper Neutralization of Null Byte or NUL Character

CWE-248: Uncaught Exception

Product status

< 1.4.2
affected

References

github.com/...ree5gc/security/advisories/GHSA-p9hg-pq3q-v9gv

github.com/...ommit/88de9fa74a1b3f3522e53b4cfa2d184712ffa4ee

cve.org (CVE-2026-33191)

nvd.nist.gov (CVE-2026-33191)

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