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CVE-2013-4566

14
FAUCET Score

CVE-2013-4566 describes a bypass vulnerability in mod_nss versions 1.0.8 and earlier, affecting mod_nss_project and Red Hat Enterprise Linux. When NSSVerifyClient is set to "none" at the server/vhost level, the module fails to enforce this setting within directory contexts, allowing remote attackers to circumvent access restrictions. This vulnerability has a CVSS score of 4.0, indicating a medium severity with network access, high attack complexity, and potential for partial confidentiality and integrity impact. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 1.0.8CPE matchmatch criteria
cpe:2.3:a:mod_nss_project:mod_nss:*:*:*:*:*:*:*:*
1.0CPE matchmatch criteria
cpe:2.3:a:mod_nss_project:mod_nss:1.0:*:*:*:*:*:*:*
1.0.2CPE matchmatch criteria
cpe:2.3:a:mod_nss_project:mod_nss:1.0.2:*:*:*:*:*:*:*
1.0.3CPE matchmatch criteria
cpe:2.3:a:mod_nss_project:mod_nss:1.0.3:*:*:*:*:*:*:*
1.0.4CPE matchmatch criteria
cpe:2.3:a:mod_nss_project:mod_nss:1.0.4:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

4.0MEDIUM

AV:N/AC:H/Au:N/C:P/I:P/A:N

Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
NONE
Access Vector
NETWORK
Access Complexity
HIGH
Authentication
NONE
Exploitability Score
4.9
Impact Score
4.9
CvssVersion
2.0

Exploit Intelligence

EPSS Score
2.00%
Probability of exploitation in next 30 days
EPSS Percentile
78.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0200 is in the 64th percentile among its peer group of 19,955 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: mod_nss-0:1.0.8-8.el5_10
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: mod_nss-0:1.0.8-19.el6_5
View patch
redhatend of lifevia redhat_api
Product: Red Hat Certificate System 8Fixed in: mod_nss
redhatend of lifevia redhat_api
Product: Red Hat Directory Server 8Fixed in: fortitude-mod_nss

Vendor Advisories (1)

redhatCVE-2013-4566Moderate

mod_nss: incorrect handling of NSSVerifyClient in directory context

Dec 3, 2013

References

lists.opensuse.org / opensuse-updates/2013-12/msg00118.html
rhn.redhat.com / errata/RHSA-2013-1779.html
bugzilla.redhat.com / show_bug.cgi