CVE-2026-44319: free5gc Input Validation Flaw — Exploit

Description

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF terminates the entire process when a stored PFD-subscription notifyUri cannot be reached. In PfdChangeNotifier.FlushNotifications(), the notifier calls NnefPFDmanagementNotify(...) and on any delivery error invokes logger.PFDManageLog.Fatal(err), which is os.Exit(1)-equivalent in Go. An attacker who can create a PFD subscription with an attacker-chosen notifyUri and then trigger a PFD change can deterministically kill NEF on the asynchronous delivery attempt -- the process exits with status 1, dropping NEF's entire SBI surface until restart. This vulnerability is fixed in 4.2.2.

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CVSS v3.1 Score

7.5

HIGH

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

EPSS — Exploit Prediction

0.0039

Probability of exploitation

0.30%

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-20 Improper Input Validation

CWE-617 CWE-617

CWE-755 CWE-755

Affected Products

Vendor	Product	Versions
free5gc	free5gc	< 4.2.2

References

Advisories & Patches

https://github.com/free5gc/free5gc/security/advisories/GHSA-rxrq-fv76-26pr https://github.com/free5gc/nef/commit/f110517b1189801950b50668a593398687049074 https://github.com/free5gc/nef/pull/25 https://github.com/free5gc/free5gc/security/advisories/GHSA-rxrq-fv76-26pr

Exploits

https://github.com/free5gc/free5gc/issues/924 https://github.com/free5gc/free5gc/security/advisories/GHSA-rxrq-fv76-26pr https://github.com/free5gc/free5gc/issues/924 https://github.com/free5gc/free5gc/security/advisories/GHSA-rxrq-fv76-26pr

Frequently Asked Questions

What is CVE-2026-44319? +

free5GC is an open-source implementation of the 5G core network. Prior to 4.2.2, free5GC's NEF terminates the entire process when a stored PFD-subscription notifyUri cannot be reached. In PfdChangeNotifier.FlushNotifications(), the notifier calls NnefPFDmanagementNotify(...) and on any delivery error invokes logger.PFDManageLog.Fatal(err), which is os.Exit(1)-equivalent in Go. An attacker who can create a PFD subscription with an attacker-chosen notifyUri and then trigger a PFD change can deterministically kill NEF on the asynchronous delivery attempt -- the process exits with status 1, dropping NEF's entire SBI surface until restart. This vulnerability is fixed in 4.2.2. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-44319? +

CVE-2026-44319 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0039, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-44319? +

CVE-2026-44319 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-2026-44319? +

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.

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