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Fencer Vulns
high 7.2

CVE-2005-0021 json

Multiple buffer overflows in Exim before 4.43 may allow attackers to execute arbitrary code via (1) an IPv6 address with more than 8 compon…

published 2005-01-06 21 y ago modified 2026-06-16 4 mo ago also EUVD-2005-0022

cvss
7.2
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.6%
EPSS 2.6% chance of exploitation in 30 days, percentile 85%
public exploits
2
Exploit-DB

Summary

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.

Patch / fix

  • exim4 Debian 14, Debian 13, Debian 12 4.34-10

debian advisories DEBIAN-CVE-2005-0021

  • exim RHEL 4 4.43-1.RHEL4.3
  • exim-sa RHEL 4 4.43-1.RHEL4.3
  • exim-mon RHEL 4 4.43-1.RHEL4.3

red hat advisories RHSA-2005:025

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2005-0021 updated

security flaw

  • Red Hat Enterprise Linux AS version 4 exim 4.43-1.RHEL4.3, exim-sa 4.43-1.RHEL4.3, exim-mon 4.43-1.RHEL4.3 Red Hat Enterprise Linux Desktop version 4 exim 4.43-1.RHEL4.3, exim-sa 4.43-1.RHEL4.3, exim-mon 4.43-1.RHEL4.3 Red Hat Enterprise Linux ES version 4 exim 4.43-1.RHEL4.3, exim-sa 4.43-1.RHEL4.3, exim-mon 4.43-1.RHEL4.3 Red Hat Enterprise Linux WS version 4 exim 4.43-1.RHEL4.3, exim-sa 4.43-1.RHEL4.3, exim-mon 4.43-1.RHEL4.3
    fixed: vendor fix RHSA-2005:025

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. Published
  2. First public exploit (EDB-756)

Exploit prediction

2.62% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-1009 Exim 4.41 - 'dns_build_reverse' Local Read Emails local, 2005-05-25
  • EDB-756 Exim 4.41 - 'dns_build_reverse' Local Buffer Overflow local, 2005-01-15
  • idefense.com http://www.idefense.com/application/poi/display?id=183&type=vulnerabilities referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.