Cloud Vulnerability DB
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Vulnerability DatabaseCVE-2020-28013
CVE-2020-28013:
Exim vulnerability analysis and mitigation
Overview
CVE-2020-28013 is a heap buffer overflow vulnerability in Exim mail server versions before 4.94.2. The vulnerability occurs in the parsefixphrase() function when handling '-F '.('' on the command line. This vulnerability was discovered as part of the '21Nails' vulnerabilities audit of Exim (Qualys Advisory).
Technical details
The vulnerability occurs when a local attacker executes Exim with a -F '.('' option. In this case, parsefixphrase() calls strncpy() with a -1 size, which causes a heap buffer overflow because strncpy() writes additional null bytes to ensure a total of n bytes are written. The overflow happens because at a specific code point, variables s and ss are both equal to end, ss is decremented, and ss-s becomes equal to -1 (Qualys Advisory).
Impact
If successfully exploited, this vulnerability could allow an unprivileged local attacker to obtain full root privileges on the system (Qualys Advisory).
Mitigation and workarounds
The vulnerability was fixed in Exim version 4.94.2. Users should upgrade to this version or later to protect against this vulnerability (NVD).
Additional resources
Source: This report was generated using AI
Related Exim vulnerabilities:
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