# CVE-2013-2566

## Summary

- **CVE ID:** CVE-2013-2566
- **Severity:** MEDIUM
- **CVSS Score:** 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N)
- **CWE:** N/A
- **Published:** Mar 14, 2013
- **Last Modified:** May 22, 2026

## 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.

## Affected Products

- n/a — n/a (n/a)

## References

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

## Exploitation Prediction (EPSS)

- **EPSS Score:** 90.32%
- **EPSS Percentile:** 99.6

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-17._