How severe is CVE-2013-2566?

CVE-2013-2566 has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2013-2566?

Affected package information for CVE-2013-2566 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2013-2566?

No fixed version has been published for CVE-2013-2566 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2013-2566 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2013-2566, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

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

CVE-2013-2566 has an EPSS (Exploit Prediction Scoring System) score of 93.2%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2013-2566?

CVE-2013-2566 is classified as CWE-326 (CWE-326), Broken Cryptographic Algorithm (CWE-327). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Which products and versions are affected by CVE-2013-2566?

CVE-2013-2566 affects canonical ubuntu linux (4 versions, e.g. 12.04, 12.10, 13.04…); fujitsu m10-1 firmware; fujitsu m10-4 firmware; fujitsu m10-4s firmware, and 12 more product(s). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2013-2566 published, and has it been updated?

CVE-2013-2566 was published on March 15, 2013 and was last updated on May 22, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2013-2566

MEDIUM

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…

Published

Mar 15, 2013

Updated

May 22, 2026

Affected

0 pkgs

Patched

None yet

Exploits

1 known

EPSS Exploitation Probability

via FIRST.org ↗

93.2%probability of exploitation in next 30 days

Very High Risk100th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

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

16 products · 26 configurations

ubuntu linuxcanonical

4 versions

12.0412.1013.0413.10

m10-1 firmwarefujitsu

≥ xcp && < xcp2280

range

m10-4 firmwarefujitsu

≥ xcp && < xcp2280

range

m10-4s firmwarefujitsu

≥ xcp && < xcp2280

range

sparc enterprise m3000 firmwarefujitsu

≥ xcp && < xcp_1121

range

sparc enterprise m4000 firmwarefujitsu

≥ xcp && < xcp_1121

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

The RC4 algorithm, as used in the TLS protocol and SSL protocol, has man…

github.comMetasploitNov 2022

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2013-2566 in your stack?

O3 detects CVE-2013-2566 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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