High severity · published May 27, 2026
CVE-2026-42459
free5GC: Improper Input Validation and Generation of Error Message Containing Sensitive Information in github.com/free5gc/udm
7.5
CVSS
0.3%
EPSS
No
On KEV
Description
free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, the free5GC UDM component fails to validate the supi path parameter in six GET handlers of the nudm-sdm (Subscriber Data Management) service. An unauthenticated attacker can inject control characters into the SUPI parameter, causing UDM to forward a malformed request to UDR and return a 500 Internal Server Error response that exposes internal infrastructure details. This vulnerability is fixed in 4.2.2.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
free5gc · free5gc
< 4.2.2 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42459
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-42459
Exploit
https://github.com/free5gc/free5gc/security/advisories/GHSA-585v-hcgf-jhfr
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