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CVE-2013-2566

80
FAUCET Score

CVE-2013-2566 describes a weakness in the RC4 algorithm, as used in TLS and SSL protocols, due to single-byte biases that facilitate plaintext-recovery attacks through statistical analysis of ciphertext across numerous sessions. This vulnerability impacts products from vendors such as Canonical, Fujitsu, Mozilla, and Oracle. With a CVSS score of 5.9 (Medium) and a FAUCET Risk Score of 99/100, it presents a high confidentiality impact with high attack complexity, allowing remote attackers to potentially recover sensitive data. While not listed in KEV and with no public exploit code on ExploitDB, there is a Metasploit auxiliary module for version detection, and it has garnered significant community discussion and media coverage, indicating awareness despite its inactive Hot List status.

Impacted Technologies

VendorProductVersion(s)CPE
>= 3.0.0, <= 3.9.1CPE matchmatch criteria
cpe:2.3:a:oracle:communications_application_session_controller:*:*:*:*:*:*:*:*
11.1.1.7.0CPE matchmatch criteria
cpe:2.3:a:oracle:http_server:11.1.1.7.0:*:*:*:*:*:*:*
11.1.1.9.0CPE matchmatch criteria
cpe:2.3:a:oracle:http_server:11.1.1.9.0:*:*:*:*:*:*:*
12.1.3.0.0CPE matchmatch criteria
cpe:2.3:a:oracle:http_server:12.1.3.0.0:*:*:*:*:*:*:*
12.2.1.1.0CPE matchmatch criteria
cpe:2.3:a:oracle:http_server:12.2.1.1.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

5.9MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
3.6
CvssVersion
3.0

Exploit Intelligence

EPSS Score
84.42%
Probability of exploitation in next 30 days
EPSS Percentile
99.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-24
Model: v2026.06.15
Metasploit: SSL/TLS Version Detection · Oct 14, 2014
This CVE's current EPSS score of 0.8442 is in the 100th percentile among its peer group of 19,953 CVEs.

Social Chatter

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

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

Remediation

Vendor Patches (6)

redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: gnutls
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: nss
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: openssl
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: gnutls
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: nss
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: openssl

Vendor Advisories (1)

redhatCVE-2013-2566Moderate

SSL/TLS: Attack against RC4 stream cipher

Mar 15, 2013

References

blog.cryptographyengineering.com / 2013/03/attack-of-week-rc4-is-kind-of-broken-in.html
Third Party Advisory
cr.yp.to / talks/2013.03.12/slides.pdf
Third Party Advisory
kb.juniper.net / InfoCenter/index
Third Party Advisory
marc.info
Issue TrackingThird Party Advisory
my.opera.com / securitygroup/blog/2013/03/20/on-the-precariousness-of-rc4
Third Party Advisory
security.gentoo.org / glsa/glsa-201406-19.xml
Third Party Advisory
h20566.www2.hpe.com / portal/site/hpsc/public/kb/docDisplay
Third Party Advisory
h20566.www2.hpe.com / portal/site/hpsc/public/kb/docDisplay
Third Party Advisory
security.gentoo.org / glsa/201504-01
Third Party Advisory
isg.rhul.ac.uk / tls
Third Party Advisory
mozilla.org / security/announce/2013/mfsa2013-103.html
Third Party Advisory
opera.com / docs/changelogs/unified/1215
Third Party Advisory
opera.com / security/advisory/1046
Third Party Advisory
oracle.com / technetwork/security-advisory/cpuapr2016v3-2985753.html
Third Party Advisory
oracle.com / technetwork/security-advisory/cpujan2018-3236628.html
Third Party Advisory
oracle.com / technetwork/security-advisory/cpujul2016-2881720.html
Third Party Advisory
oracle.com / technetwork/security-advisory/cpuoct2016-2881722.html
Third Party Advisory
oracle.com / technetwork/security-advisory/cpuoct2017-3236626.html
Third Party Advisory
securityfocus.com / bid/58796
Third Party AdvisoryVDB Entry
ubuntu.com / usn/USN-2031-1
Third Party Advisory
ubuntu.com / usn/USN-2032-1
Third Party Advisory