6.6

CVE-2026-27643: free5GC has improper error handling in NEF with information exposure

Analyzed
Published 24-02-2026Last modified 26-02-2026

Vulnerability summary

CVE-2026-27643 is a medium (CVSS 6.6) vulnerability in free5gc udr. EPSS estimates a 0.50% chance of exploitation in the next 30 days, higher than 41.5% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
36/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.6/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.50%
0%100%
Low · +0.22 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1github

Timeline

  1. 24-02-2026
    PublishedVulnerability first disclosed.
  2. 26-02-2026
    Last modifiedVulnerability information updated.

Description

free5GC UDR is the user data repository (UDR) for free5GC, an an open-source project for 5th generation (5G) mobile core networks. In versions up to and including 1.4.1, the NEF component reliably leaks internal parsing error details (e.g., invalid character 'n' after top-level value) to remote clients, which can aid attackers in service fingerprinting. All deployments of free5GC using the Nnef_PfdManagement service may be affected. free5gc/udr pull request 56 contains a patch for the issue. There is no direct workaround at the application level. The recommendation is to apply the provided patch.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

0.50%

Chance of exploitation in the next 30 days

Percentile

42%

Versus all other CVEs

30-day change

Increase +0.22 pp

From 0.27% on 22-09-2026

22-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

1 found
  • githubUnverified

    Free5Gc

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Free5gc1 product

1 vendor · 1 product

References

4 links