CVE-2026-44318: free5gc — Exploit & Fix

Description

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's BSF PUT /nbsf-management/v1/subscriptions/{subId} handler has an unsynchronized write on the global Subscriptions map. The handler first reads the map under RLock() via BSFContext.GetSubscription(subId), but if the subscription does not exist, ReplaceIndividualSubcription() writes back to the same map directly without taking the mutex (bsfContext.BsfSelf.Subscriptions[subId] = subscription). Under concurrent authenticated PUT load, one goroutine can read while another writes the map, which causes the Go runtime to abort the process with fatal error: concurrent map read and map write (Go runtime panics that come from concurrent map access bypass recover() and terminate the process). The BSF container exits with code 2 -- the entire BSF SBI surface goes down until restart. This vulnerability is fixed in 4.2.2.

Is your site exposed to CVE-2026-44318?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

6.5

MEDIUM

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

EPSS — Exploit Prediction

0.0025

Probability of exploitation

0.16%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-362 CWE-362

CWE-820 CWE-820

Affected Products

Vendor	Product	Versions
free5gc	free5gc	< 4.2.2

References

Advisories & Patches

https://github.com/free5gc/bsf/commit/277908565fd628d974a13ef562b81a8b7b519ffa https://github.com/free5gc/bsf/pull/7 https://github.com/free5gc/free5gc/security/advisories/GHSA-27ph-8q4f-h7m7 https://github.com/free5gc/free5gc/security/advisories/GHSA-27ph-8q4f-h7m7

Exploits

https://github.com/free5gc/free5gc/issues/926 https://github.com/free5gc/free5gc/security/advisories/GHSA-27ph-8q4f-h7m7 https://github.com/free5gc/free5gc/issues/926 https://github.com/free5gc/free5gc/security/advisories/GHSA-27ph-8q4f-h7m7

Frequently Asked Questions

What is CVE-2026-44318? +

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's BSF PUT /nbsf-management/v1/subscriptions/{subId} handler has an unsynchronized write on the global Subscriptions map. The handler first reads the map under RLock() via BSFContext.GetSubscription(subId), but if the subscription does not exist, ReplaceIndividualSubcription() writes back to the same map directly without taking the mutex (bsfContext.BsfSelf.Subscriptions[subId] = subscription). Under concurrent authenticated PUT load, one goroutine can read while another writes the map, which causes the Go runtime to abort the process with fatal error: concurrent map read and map write (Go runtime panics that come from concurrent map access bypass recover() and terminate the process). The BSF container exits with code 2 -- the entire BSF SBI surface goes down until restart. This vulnerability is fixed in 4.2.2. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-44318? +

CVE-2026-44318 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0025, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-44318? +

CVE-2026-44318 affects products from free5gc, specifically: free5gc. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-44318? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-41458

OwnTone Server versions 28.4 through 29.0 contain a race condition vulnerability in the DAAP login handler that allows unauthenticated attackers …

CVE-2025-13036

An authentication bypass security issue exists within FactoryTalk Historian Site Edition. By continually sending requests to the login endpoint, an …

CVE-2025-0372

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in HYPR Passwordless on Windows allows Privilege Escalation.This issue …

CVE-2025-59052

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Angular uses a …

CVE-2024-47534

go-tuf is a Go implementation of The Update Framework (TUF). The go-tuf client inconsistently traces the delegations. For example, if …

CVE-2025-64118

node-tar is a Tar for Node.js. In 7.5.1, using .t (aka .list) with { sync: true } to read tar …