VulnerabilityModified

CVE-2013-2566

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…

MEDIUM 5.9EPSS 84.4%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 84.4%, higher than 100% of all known CVEs. Patch or mitigate before the next change window.

Description

CVSS 3.1: 5.9 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS: 84.42% probability · 100th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Weakness: CWE-326, CWE-327
Affected: oracle/communications application session controller · oracle/http server · oracle/integrated lights out manager firmware · fujitsu/sparc enterprise m3000 firmware · fujitsu/sparc enterprise m4000 firmware · fujitsu/sparc enterprise m5000 firmware · fujitsu/sparc enterprise m8000 firmware · fujitsu/sparc enterprise m9000 firmware · fujitsu/m10-1 firmware · fujitsu/m10-4 firmware · fujitsu/m10-4s firmware · canonical/ubuntu linux · mozilla/firefox · mozilla/seamonkey · mozilla/thunderbird · mozilla/thunderbird esr
Source: cve@mitre.org

EPSS trend

EPSS moved from 77.7% on 21 September 2026 to 84.4% on 4 November 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.

References

http://blog.cryptographyengineering.com/2013/03/attack-of-week-rc4-is-kind-of-broken-in.htmlThird Party Advisory
http://cr.yp.to/talks/2013.03.12/slides.pdfThird Party Advisory
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705Third Party Advisory
http://marc.info/?l=bugtraq&m=143039468003789&w=2Issue Tracking, Third Party Advisory
http://my.opera.com/securitygroup/blog/2013/03/20/on-the-precariousness-of-rc4Third Party Advisory
http://security.gentoo.org/glsa/glsa-201406-19.xmlThird Party Advisory
http://www.isg.rhul.ac.uk/tls/Third Party Advisory
http://www.mozilla.org/security/announce/2013/mfsa2013-103.htmlThird Party Advisory
http://www.opera.com/docs/changelogs/unified/1215/Third Party Advisory
http://www.opera.com/security/advisory/1046Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpuapr2016v3-2985753.htmlThird Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.htmlThird Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.htmlThird Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.htmlThird Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.htmlThird Party Advisory
http://www.securityfocus.com/bid/58796Third Party Advisory, VDB Entry
http://www.ubuntu.com/usn/USN-2031-1Third Party Advisory
http://www.ubuntu.com/usn/USN-2032-1Third Party Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05289935Third Party Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05336888Third Party Advisory
https://security.gentoo.org/glsa/201504-01Third Party Advisory
http://blog.cryptographyengineering.com/2013/03/attack-of-week-rc4-is-kind-of-broken-in.htmlThird Party Advisory
http://cr.yp.to/talks/2013.03.12/slides.pdfThird Party Advisory
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705Third Party Advisory
http://marc.info/?l=bugtraq&m=143039468003789&w=2Issue Tracking, Third Party Advisory
http://my.opera.com/securitygroup/blog/2013/03/20/on-the-precariousness-of-rc4Third Party Advisory
http://security.gentoo.org/glsa/glsa-201406-19.xmlThird Party Advisory
http://www.isg.rhul.ac.uk/tls/Third Party Advisory
http://www.mozilla.org/security/announce/2013/mfsa2013-103.htmlThird Party Advisory
http://www.opera.com/docs/changelogs/unified/1215/Third Party Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.