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CVE-2011-4973

27
FAUCET Score

CVE-2011-4973 describes a critical authentication bypass vulnerability in mod_nss version 1.0.8. This flaw allows remote attackers to impersonate legitimate users by presenting a valid certificate and using "password" as the password, effectively bypassing intended authentication mechanisms. With a CVSS score of 9.8, this vulnerability is easily exploitable over the network with no user interaction, leading to complete compromise of confidentiality, integrity, and availability. Despite its high severity, there is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this decade-old vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
1.0.8CPE matchmatch criteria
cpe:2.3:a:mod_nss_project:mod_nss:1.0.8:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

9.8CRITICAL

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
1.02%
Probability of exploitation in next 30 days
EPSS Percentile
59.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-24
Model: v2026.06.15
This CVE's current EPSS score of 0.0102 is in the 45th percentile among its peer group of 36,829 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 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-0:1.0.8-7.el5
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: mod_nss-0:1.0.8-13.el6
View patch
redhatno patchvia redhat_api
Product: Red Hat Certificate System 8Fixed in: mod_nss
redhatno patchvia redhat_api
Product: Red Hat Directory Server 8Fixed in: fortitude-mod_nss

Vendor Advisories (1)

redhatCVE-2011-4973Moderate

mod_nss: FakeBasicAuth authentication bypass

May 4, 2011

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingThird Party Advisory
redhat.com / archives/mod_nss-list/2011-May/msg00001.html
Issue TrackingThird Party Advisory