CVE-2026-53551

See a problem?
Please try reporting it to the source first.
Source
https://cve.org/CVERecord?id=CVE-2026-53551
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53551.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-53551
Aliases
Published
2026-07-31T20:12:57.932Z
Modified
2026-08-02T03:47:50.012645374Z
Severity
  • 6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N CVSS Calculator
Summary
free5GC AUSF: null byte injection in supiOrSuci causes HTTP 500 internal service failure
Details

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.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53551.json",
    "cwe_ids": [
        "CWE-20"
    ],
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/free5gc/ausf

Affected ranges

Type
GIT
Repo
https://github.com/free5gc/ausf
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
bfc4a10094dbacbd862baa4686829f3fcc06ce1e
Fixed
b74ee7dafec5975e3440ae95125994565cfb0496
Database specific 
{
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "1.4.5"
        }
    ]
}
Type
GIT
Repo
https://github.com/free5gc/free5gc
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
8b0f4445fc931638fb624463ce3572a203517679
Database specific 
{
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "4.2.2"
        }
    ]
}

Affected versions

v1.*
v1.0.0
v1.0.1
v1.0.2
v1.1.0
v1.1.1
v1.2.0
v1.2.1
v1.2.2
v1.2.3
v1.2.4
v1.3.0
v1.3.1
v1.3.2
v1.4.0
v1.4.1
v1.4.2
v1.4.3
v1.4.4
v3.*
v3.0.5
v3.0.6
v3.0.7
v3.1.0
v3.1.1
v3.2.0
v3.2.1
v3.3.0
v3.4.0
v3.4.1
v3.4.2
v3.4.3
v3.4.4
v3.4.5
v4.*
v4.0.0
v4.0.1
v4.1.0
v4.2.0
v4.2.1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53551.json"