free5GC UDR: Fail-open handling in PolicyDataSubsToNotifyPost allows unintended subscription creation

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-40343: 8.63% estimated exploitation activity in the next 30 days; percentile 95.11 (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 A fail-open request handling flaw in the UDR service causes the /nudr-dr/v2/policy-data/subs-to-notify POST handler to continue processing requests even after request body retrieval or deserialization errors. This may allow unintended creation of Policy Data notification subscriptions with invalid, empty, or partially processed input, depending on downstream processor behavior. Details The endpoint POST /nudr-dr/v2/policy-data/subs-to-notify is intended to create a Policy Data notification subscription only after the HTTP request body has been successfully read and parsed into a valid PolicyDataSubscription object. [file:93] In the free5GC UDR implementation, the function HandlePolicyDataSubsToNotifyPost in NFs/udr/internal/sbi/apidatarepository.go does not terminate execution after input-processing failures. [file:93] The request flow is: 1. The handler calls c.GetRawData() to read the HTTP request body. [file:93] 2. If GetRawData() fails, the handler sends an HTTP 500 error…

Published by the source

21 Apr 2026, 19:05 UTC

Last modified by the source

24 Apr 2026, 21:11 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jwch-w7wh-gqjm

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# Patch Next advisory brief: CVE-2026-40343

Advisory: free5GC UDR: Fail-open handling in PolicyDataSubsToNotifyPost allows unintended subscription creation
IDs: CVE-2026-40343, GHSA-jwch-w7wh-gqjm
Record: https://patchnext.com/advisories/cve-2026-40343 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
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/udr: affected <= 1.4.2

## Suggested inspection (read-only)
- Go github.com/free5gc/udr: 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/udr.
- 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-jwch-w7wh-gqjm (GitHub-reviewed advisory GHSA-jwch-w7wh-gqjm lists affected ranges: Go github.com/free5gc/udr >=0 <=1.4.2)

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