What’s Vulnerable › Vulnerabilities

CVE-2013-4207

• Severity: medium (CVSS 4.3 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2013-08-19 · updated 2026-06-16
• Weakness: CWE-119

Description

Buffer overflow in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) via an invalid DSA signature that is not properly handled during computation of a modular inverse and triggers the overflow during a division by zero by the bignum functionality, a different vulnerability than CVE-2013-4206.

Affected products

• PuTTY: 0.45, 0.46, 0.47, 0.48, 0.49, 0.50 (+12)
• Simon Tatham Putty: through 0.62; 0.53

References

• http://lists.opensuse.org/opensuse-updates/2013-08/msg00035.html
• http://secunia.com/advisories/54379
• http://secunia.com/advisories/54533
• http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-bignum-division-by-zero.html
• http://www.debian.org/security/2013/dsa-2736
• http://www.openwall.com/lists/oss-security/2013/08/06/11
• http://lists.opensuse.org/opensuse-updates/2013-08/msg00035.html
• http://secunia.com/advisories/54379
• http://secunia.com/advisories/54533
• http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-bignum-division-by-zero.html
• http://www.debian.org/security/2013/dsa-2736
• http://www.openwall.com/lists/oss-security/2013/08/06/11

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