Is CVE-2013-4566 being actively exploited?

CVE-2013-4566 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2013-4566?

CVE-2013-4566 has a CVSS 2.0 base score of 4.0 (MEDIUM).

CVE-2013-4566

MEDIUM · CVSS 4.0EPSS 1.9%EU EUVD

mod_nss 1.0.8 and earlier, when NSSVerifyClient is set to none for the server/vhost context, does not enforce the NSSVerifyClient setting in the directory context, which allows remote attackers to bypass intended access restrictions.

Key facts

CVSS score: 4.0 (v2.0)
Severity: MEDIUM
CVSS vector: AV:N/AC:H/Au:N/C:P/I:P/A:N
Weakness (CWE): CWE-264
EPSS score: 1.9% (80th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2013-4424)
Published: December 12, 2013
NVD last modified: June 16, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2013-4424 in the EU Vulnerability Database. Last updated in EUVD on August 6, 2024.

View on the EU Vulnerability Database

Affected products

mod nss project / mod nss
mod nss project / mod nss
mod nss project / mod nss
mod nss project / mod nss
mod nss project / mod nss
mod nss project / mod nss
mod nss project / mod nss
mod nss project / mod nss
redhat / enterprise linux
redhat / enterprise linux

Certified products that may be affected

6 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Red Hat Enterprise Linux 5 OpenSSH-Server Cryptographic Module - Red Hat®, Inc. - FIPS 140 1384 - historical
Red Hat Enterprise Linux 5 OpenSSH Client Cryptographic Module - Red Hat®, Inc. - FIPS 140 1385 - historical
Red Hat Enterprise Linux 5 OpenSwan Cryptographic Module - Red Hat®, Inc. - FIPS 140 1386 - historical
Red Hat Enterprise Linux 5 Kernel Crypto API Cryptographic Module - Red Hat®, Inc. - FIPS 140 1387 - historical
Red Hat Enterprise Linux 5 OpenSSL Cryptographic Module - Red Hat®, Inc. - FIPS 140 1320 - historical

See all 6 in the Security Certifications Explorer.

References

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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