free5GC PCF: Memory Leak via CORS Middleware Registration in HTTP Handler Leads to Denial of Service

Exploitation

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

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-41135: 0.52% estimated exploitation activity in the next 30 days; percentile 43.90 (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 memory leak vulnerability in the free5GC PCF (Policy Control Function) allows any unauthenticated attacker with network access to the PCF SBI interface to cause uncontrolled memory growth by sending repeated HTTP requests to the OAM endpoint. The root cause is a router.Use() call inside an HTTP handler that registers a new CORS middleware on every incoming request, permanently growing the Gin router's handler chain. This leads to progressive memory exhaustion and eventual Denial of Service of the PCF, preventing all UEs from obtaining AM and SM policies and blocking 5G session establishment. Details File: free5gc/pcf/internal/sbi/apioam.go Function: setCorsHeader(), called by HTTPOAMGetAmPolicy() The function setCorsHeader() invokes s.router.Use() on every incoming HTTP request: In the Gin framework, router.Use() appends a new HandlerFunc to the router's internal middleware slice. This operation is not idempotent — it does not replace existing middleware but appends a new…

Published by the source

22 Apr 2026, 19:49 UTC

Last modified by the source

22 Apr 2026, 19:49 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-98cp-84m9-q3qp

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# Patch Next advisory brief: CVE-2026-41135

Advisory: free5GC PCF: Memory Leak via CORS Middleware Registration in HTTP Handler Leads to Denial of Service
IDs: CVE-2026-41135, GHSA-98cp-84m9-q3qp
Record: https://patchnext.com/advisories/cve-2026-41135 (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: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/free5gc/pcf 1.4.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/free5gc/pcf: affected < 1.4.3; fixed in 1.4.3

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

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/free5gc/pcf.
- 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-98cp-84m9-q3qp (GitHub-reviewed advisory GHSA-98cp-84m9-q3qp lists affected ranges: Go github.com/free5gc/pcf >=0 <1.4.3)

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