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Fencer Vulns
medium 6.4

CVE-2009-2666 json

socket.c in fetchmail before 6.3.11 does not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of a…

published 2009-08-07 17 y ago modified 2026-06-16 4 mo ago also EUVD-2009-2659

cvss
6.4
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
0
none known

Summary

socket.c in fetchmail before 6.3.11 does not properly handle a '\0' character in a domain name in the subject's Common Name (CN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

Patch / fix

  • fetchmail Debian 14, Debian 13, Debian 12 6.3.9~rc2-6

debian advisories DEBIAN-CVE-2009-2666

  • fetchmail RHEL 3 6.2.0-3.el3.5
  • fetchmail RHEL 4 6.2.5-6.0.1.el4_8.1
  • fetchmail RHEL 5 6.3.6-1.1.el5_3.1

red hat advisories RHSA-2009:1427

  • fetchmail openSUSE Tumbleweed 6.3.26-13.4

opensuse advisories openSUSE-SU-2024:10194-1

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-2009-2666 updated cvss 4.3

fetchmail: SSL null terminator bypass

  • Red Hat Desktop version 3 fetchmail 6.2.0-3.el3.5 Red Hat Enterprise Linux (v. 5 server) fetchmail 6.3.6-1.1.el5_3.1 Red Hat Enterprise Linux AS version 3 fetchmail 6.2.0-3.el3.5 Red Hat Enterprise Linux AS version 4 fetchmail 6.2.5-6.0.1.el4_8.1 Red Hat Enterprise Linux Desktop version 4 fetchmail 6.2.5-6.0.1.el4_8.1 Red Hat Enterprise Linux Desktop Workstation (v. 5 client) fetchmail 6.3.6-1.1.el5_3.1
    +4 more products
    Red Hat Enterprise Linux ES version 3 fetchmail 6.2.0-3.el3.5 Red Hat Enterprise Linux ES version 4 fetchmail 6.2.5-6.0.1.el4_8.1 Red Hat Enterprise Linux WS version 3 fetchmail 6.2.0-3.el3.5 Red Hat Enterprise Linux WS version 4 fetchmail 6.2.5-6.0.1.el4_8.1
    fixed: vendor fix RHSA-2009:1427

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

Exploit prediction

1.50% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:P/A:N

Classification

Weakness

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.