Improper input validation in free5gc
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-209.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| free5gc | free5gc | before 4.2.2 | 4.2.2 | Patch available | CNA |
| — | github.com/free5gc/udm (Go) | up to 1.4.3 | — | No fix listed | GHSA-585v-hcgf-jhfr |
- free5gc Vendorfree5gc Affected before 4.2.2 Fixed in 4.2.2 Patch available CNA
- github.com/free5gc/udm (Go) Vendor— Affected up to 1.4.3 Fixed in — No fix listed GHSA-585v-hcgf-jhfr
Remediation
- Fix · CNA free5gc (free5gc) Fixed in 4.2.2
Timeline
- 2026-10-02 Threatist record created from CVE-2026-42459
- 2026-10-03 Alias added: GHSA-585v-hcgf-jhfr
References
More Free5gc vulnerabilities
- TI-2026-32298 Incorrect authorization in free5gc CVSS 3.1CRITICAL 10.0
- TI-2026-32297 free5GC: SMF UPI management interface lacks auth middleware; unauthenticated topology read/write requests reach handlers CVSS 3.1CRITICAL 10.0
- TI-2026-32295 free5GC: NEF nnef-oam route group is unauthenticated; no-token requests reach the OAM handler CVSS 3.1CRITICAL 10.0
- TI-2025-39412 free5gc v4.1.0 and before is vulnerable to Buffer Overflow. CVSS 3.1CRITICAL 9.8
- TI-2026-32294 Missing authorization in free5gc CVSS 3.1CRITICAL 9.4
- TI-2026-32283 Missing authorization in free5gc CVSS 3.1CRITICAL 9.4
Sources
- CVE-2026-42459 · CVE Program
- CVE-2026-42459 · NVD
- FIRST EPSS
- GHSA-585v-hcgf-jhfr · GitHub Advisory Database · CC BY 4.0
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