CVE-2005-0021

Exim < 4.43 - Buffer Overflow via IPv6 Address or DNS PTR Lookup

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2005-0021. PoCs published by Plugger, Rafael Carrasco.

AI-analyzed exploit summary This exploit targets a buffer overflow vulnerability in Exim (CVE-2005-0021) by injecting shellcode into the '-bh' argument. It uses Aleph1's shellcode to spawn a shell, with NOP sleds for padding and a hardcoded return address.

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.

Exploits (2)

exploitdb WORKING POC VERIFIED
by Plugger · clocallinux
https://www.exploit-db.com/exploits/1009

This exploit targets a buffer overflow vulnerability in Exim (CVE-2005-0021) by injecting shellcode into the '-bh' argument. It uses Aleph1's shellcode to spawn a shell, with NOP sleds for padding and a hardcoded return address.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Exim (version not specified, likely older versions)
No auth needed
Prerequisites: Local access to the target system · Exim binary present at /usr/exim/bin/exim
devstral-2 · analyzed Feb 16, 2026 Full analysis →
exploitdb WORKING POC VERIFIED
by Rafael Carrasco · clocallinux
https://www.exploit-db.com/exploits/756

This exploit targets a buffer overflow vulnerability in Exim (CVE-2005-0021) by injecting shellcode into a crafted input string passed to the `-bh` argument. The shellcode spawns a `/bin/sh` shell, and the return address is brute-forced using an accompanying Perl script.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Exim 4.41
No auth needed
Prerequisites: Exim 4.41 installed on a vulnerable system · Ability to execute the exploit locally or via command-line arguments
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (10)

Core 10
Core References
Vendor Advisory third-party-advisory x_refsource_idefense
http://www.idefense.com/application/poi/display?id=179&type=vulnerabilities
Patch, US Government Resource third-party-advisory x_refsource_cert-vn
http://www.kb.cert.org/vuls/id/132992
Vendor Advisory vendor-advisory x_refsource_debian
http://www.debian.org/security/2005/dsa-635
Vendor Advisory vendor-advisory x_refsource_debian
http://www.debian.org/security/2005/dsa-637
Exploit, Vendor Advisory third-party-advisory x_refsource_idefense
http://www.idefense.com/application/poi/display?id=183&type=vulnerabilities
Patch vendor-advisory x_refsource_redhat
http://www.redhat.com/support/errata/RHSA-2005-025.html
Vendor Advisory vendor-advisory x_refsource_gentoo
http://security.gentoo.org/glsa/glsa-200501-23.xml
Third Party Advisory, VDB Entry vdb-entry signature x_refsource_oval
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10347

Scores

EPSS 0.0262
EPSS Percentile 83.4%

Details

Status published
Products (3)
university_of_cambridge/exim 4.41
university_of_cambridge/exim 4.42
university_of_cambridge/exim < 4.40
Published May 02, 2005
Tracked Since Feb 18, 2026