Free5GC UDM has Improper Input Validation and Generation of Error Messages Containing Sensitive Information

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2026-42459: 0.32% estimated exploitation activity in the next 30 days; percentile 25.54 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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. Affected Package - Ecosystem: Go - Package: github.com/free5gc/udm - Affected versions: <= v1.4.2 - Patched versions: none yet Details The following handlers in internal/sbi/apisubscriberdatamanagement.go do not call validator.IsValidSupi() before passing the supi parameter to the processor: - HandleGetSmfSelectData — GET /:supi/smf-select-data - HandleGetSupi — GET /:supi - HandleGetTraceData — GET /:supi/trace-data - HandleGetUeContextInSmfData — GET /:supi/ue-context-in-smf-data - HandleGetNssai — GET /:supi/nssai - HandleGetSmData — GET /:supi/sm-data By contrast, HandleGetAmData in the same file correctly…

Published by the source

7 May 2026, 02:09 UTC

Last modified by the source

8 Jun 2026, 23:46 UTC

Source last checked

26 Oct 2026, 15:23 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-585v-hcgf-jhfr

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# Patch Next advisory brief: CVE-2026-42459

Advisory: Free5GC UDM has Improper Input Validation and Generation of Error Messages Containing Sensitive Information
IDs: CVE-2026-42459, GHSA-585v-hcgf-jhfr
Record: https://patchnext.com/advisories/cve-2026-42459 (revision 1, source checked 26 Oct 2026, 15:23 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/free5gc/udm: affected <= 1.4.3

## Suggested inspection (read-only)
- Go github.com/free5gc/udm: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/free5gc/udm.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-585v-hcgf-jhfr (GitHub-reviewed advisory GHSA-585v-hcgf-jhfr lists affected ranges: Go github.com/free5gc/udm >=0 <=1.4.3)

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