CVE-2005-0021
NVD-CWE-OtherPublished: May 2, 2005· Updated: Jun 16, 2026
Official Description
Multiple buffer overflows in Exim before 4.43 may allow attackers to execute arbitrary code via (1) an IPv6 address with more than 8 components, as demonstrated using the -be command line option, which triggers an overflow in the host_aton function, or (2) the -bh command line option or dnsdb PTR lookup, which triggers an overflow in the dns_build_reverse function.
Technical Analysis
CVE-2005-0021 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A proof-of-concept (PoC) exploit exists for CVE-2005-0021. While not yet confirmed in active campaigns, the availability of PoC code increases exploitation risk substantially.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (20)
Quick Facts
Related CVEs (NVD-CWE-Other)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2005-0021 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts