CVE-2013-7040

Severity: medium (CVSS 4.3 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2014-05-19 · updated 2026-06-17
Weakness: CWE-310

Description

Python 2.7 before 3.4 only uses the last eight bits of the prefix to randomize hash values, which causes it to compute hash values without restricting the ability to trigger hash collisions predictably and makes it easier for context-dependent attackers to cause a denial of service (CPU consumption) via crafted input to an application that maintains a hash table. NOTE: this vulnerability exists because of an incomplete fix for CVE-2012-1150.

Affected products

macOS: through 10.10.4
Python: 2.7.1, 2.7.1-rc1, 2.7.2-rc1, 2.7.3, 2.7.4, 2.7.5 (+35)

References

http://bugs.python.org/issue14621
http://lists.apple.com/archives/security-announce/2015/Aug/msg00001.html
http://www.openwall.com/lists/oss-security/2013/12/09/13
http://www.openwall.com/lists/oss-security/2013/12/09/3
http://www.securityfocus.com/bid/64194
https://support.apple.com/kb/HT205031
http://bugs.python.org/issue14621
http://lists.apple.com/archives/security-announce/2015/Aug/msg00001.html
http://www.openwall.com/lists/oss-security/2013/12/09/13
http://www.openwall.com/lists/oss-security/2013/12/09/3
http://www.securityfocus.com/bid/64194
https://support.apple.com/kb/HT205031

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