{"id":"CVE-2013-2566","url":"https://www.cyber-defence.io/tools/cve/CVE-2013-2566","generatedAt":"2026-11-05T07:40:07.022Z","title":"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…","description":"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.","published":"2013-03-15T21:55:01.000Z","lastModified":"2026-06-16T23:53:39.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},"cwe":["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"],"epss":{"score":0.84424,"percentile":0.99701,"date":"2026-11-04","history":[{"date":"2026-09-21","score":0.7767,"percentile":0.99556},{"date":"2026-09-22","score":0.84424,"percentile":0.99689}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"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."},"changes":[{"kind":"epss","label":"EPSS jump","at":"2026-09-22T00:00:00.000Z","detail":{"to":0.84424,"from":0.7767,"percentile":0.99689},"summary":"EPSS moved from 77.7% to 84.4% probability of exploitation in the next thirty days."}],"references":[{"url":"http://blog.cryptographyengineering.com/2013/03/attack-of-week-rc4-is-kind-of-broken-in.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://cr.yp.to/talks/2013.03.12/slides.pdf","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://marc.info/?l=bugtraq&m=143039468003789&w=2","tags":["Issue Tracking","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://my.opera.com/securitygroup/blog/2013/03/20/on-the-precariousness-of-rc4","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://security.gentoo.org/glsa/glsa-201406-19.xml","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.isg.rhul.ac.uk/tls/","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.mozilla.org/security/announce/2013/mfsa2013-103.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.opera.com/docs/changelogs/unified/1215/","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.opera.com/security/advisory/1046","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpuapr2016v3-2985753.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/bid/58796","tags":["Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"http://www.ubuntu.com/usn/USN-2031-1","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.ubuntu.com/usn/USN-2032-1","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05289935","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05336888","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://security.gentoo.org/glsa/201504-01","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://blog.cryptographyengineering.com/2013/03/attack-of-week-rc4-is-kind-of-broken-in.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://cr.yp.to/talks/2013.03.12/slides.pdf","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://marc.info/?l=bugtraq&m=143039468003789&w=2","tags":["Issue Tracking","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://my.opera.com/securitygroup/blog/2013/03/20/on-the-precariousness-of-rc4","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://security.gentoo.org/glsa/glsa-201406-19.xml","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.isg.rhul.ac.uk/tls/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.mozilla.org/security/announce/2013/mfsa2013-103.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.opera.com/docs/changelogs/unified/1215/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.opera.com/security/advisory/1046","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpuapr2016v3-2985753.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securityfocus.com/bid/58796","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.ubuntu.com/usn/USN-2031-1","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.ubuntu.com/usn/USN-2032-1","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05289935","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05336888","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/201504-01","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2013-2566","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}