Is CVE-2013-2566 being actively exploited?

CVE-2013-2566 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2013-2566?

CVE-2013-2566 has a CVSS 3.1 base score of 5.9 (MEDIUM).

CVE-2013-2566

MEDIUM · CVSS 5.9EPSS 84.4%EU EUVD

The RC4 algorithm, as used in the TLS protocol and SSL protocol, has many single-byte biases, which makes it easier for remote attackers to conduct plaintext-recovery attacks via statistical analysis of ciphertext in a large number of sessions that use the same plaintext.

Key facts

CVSS score: 5.9 (v3.1)
Severity: MEDIUM
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness (CWE): CWE-326
EPSS score: 84.4% (100th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2013-2508)
Published: March 15, 2013
NVD last modified: June 16, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2013-2508 in the EU Vulnerability Database. Last updated in EUVD on May 22, 2026.

View on the EU Vulnerability Database

Affected products

canonical / ubuntu linux
canonical / ubuntu linux
canonical / ubuntu linux
canonical / ubuntu linux
fujitsu / m10-1
fujitsu / m10-1 firmware
fujitsu / m10-4
fujitsu / m10-4 firmware
fujitsu / m10-4s
fujitsu / m10-4s firmware
fujitsu / sparc enterprise m3000
fujitsu / sparc enterprise m3000 firmware
fujitsu / sparc enterprise m4000
fujitsu / sparc enterprise m4000 firmware
fujitsu / sparc enterprise m5000
fujitsu / sparc enterprise m5000 firmware
fujitsu / sparc enterprise m8000
fujitsu / sparc enterprise m8000 firmware
fujitsu / sparc enterprise m9000
fujitsu / sparc enterprise m9000 firmware
mozilla / firefox
mozilla / seamonkey
mozilla / thunderbird
mozilla / thunderbird esr
oracle / communications application session controller
oracle / http server
oracle / http server
oracle / http server
oracle / http server
oracle / http server
oracle / integrated lights out manager firmware

References

http://blog.cryptographyengineering.com/2013/03/attack-of-week-rc4-is-kind-of-broken-in.html(Third Party Advisory)
http://cr.yp.to/talks/2013.03.12/slides.pdf(Third Party Advisory)
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705(Third Party Advisory)
http://marc.info/?l=bugtraq&m=143039468003789&w=2(Issue Tracking, Third Party Advisory)
http://my.opera.com/securitygroup/blog/2013/03/20/on-the-precariousness-of-rc4(Third Party Advisory)
http://security.gentoo.org/glsa/glsa-201406-19.xml(Third Party Advisory)
http://www.isg.rhul.ac.uk/tls/(Third Party Advisory)
http://www.mozilla.org/security/announce/2013/mfsa2013-103.html(Third Party Advisory)
http://www.opera.com/docs/changelogs/unified/1215/(Third Party Advisory)
http://www.opera.com/security/advisory/1046(Third Party Advisory)
http://www.oracle.com/technetwork/security-advisory/cpuapr2016v3-2985753.html(Third Party Advisory)
http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html(Third Party Advisory)
http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html(Third Party Advisory)
http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html(Third Party Advisory)
http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html(Third Party Advisory)
http://www.securityfocus.com/bid/58796(Third Party Advisory, VDB Entry)
http://www.ubuntu.com/usn/USN-2031-1(Third Party Advisory)
http://www.ubuntu.com/usn/USN-2032-1(Third Party Advisory)
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05289935(Third Party Advisory)
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05336888(Third Party Advisory)
https://security.gentoo.org/glsa/201504-01(Third Party Advisory)

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

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