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Fencer Vulns
low 2.6

CVE-2007-1558 json

The APOP protocol allows remote attackers to guess the first 3 characters of a password via man-in-the-middle (MITM) attacks that use craft…

published 2007-04-16 19 y ago modified 2026-06-16 4 mo ago also EUVD-2007-1552

cvss
2.6
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

The APOP protocol allows remote attackers to guess the first 3 characters of a password via man-in-the-middle (MITM) attacks that use crafted message IDs and MD5 collisions. NOTE: this design-level issue potentially affects all products that use APOP, including (1) Thunderbird 1.x before 1.5.0.12 and 2.x before 2.0.0.4, (2) Evolution, (3) mutt, (4) fetchmail before 6.3.8, (5) SeaMonkey 1.0.x before 1.0.9 and 1.1.x before 1.1.2, (6) Balsa 2.3.16 and earlier, (7) Mailfilter before 0.8.2, and possibly other products.

Patch / fix

  • mutt Debian 14, Debian 13, Debian 12 1.5.18-6
  • balsa Debian 14, Debian 13, Debian 12 2.3.17-1
  • fetchmail Debian 14, Debian 13, Debian 12 6.3.8-1
  • claws-mail Debian 14, Debian 13, Debian 12 2.9.1-1
  • mailfilter Debian 14, Debian 13, Debian 12 0.8.2-1

debian advisories DEBIAN-CVE-2007-1558

  • ruby RHEL 4 1.8.1-7.el4_8.3
  • ruby RHEL 5 1.8.5-5.el5_3.7
  • irb RHEL 4 1.8.1-7.el4_8.3
  • ruby-ri RHEL 5 1.8.5-5.el5_3.7
  • ruby-irb RHEL 5 1.8.5-5.el5_3.7
  • ruby-libs RHEL 4 1.8.1-7.el4_8.3
  • ruby-libs RHEL 5 1.8.5-5.el5_3.7
  • ruby-mode RHEL 4 1.8.1-7.el4_8.3

red hat advisories RHSA-2009:1140RHSA-2007:0402RHSA-2007:0401RHSA-2007:0386RHSA-2007:0385RHSA-2007:0353

  • claws-mail openSUSE Tumbleweed 4.0.0-2.5
  • fetchmail openSUSE Tumbleweed 6.4.21-2.1
  • mutt openSUSE Tumbleweed 2.0.7-2.2
  • mpop openSUSE Tumbleweed 1.4.14-1.1

opensuse advisories openSUSE-SU-2024:10686-1openSUSE-SU-2024:10753-1openSUSE-SU-2024:11069-1openSUSE-SU-2024:11615-1

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-2007-1558 updated cvss 2.6

fetchmail/mutt/evolution/...: APOP password disclosure vulnerability

  • Red Hat Desktop version 3 mutt 1.4.1-5.el3, evolution 1.4.5-20.el3, fetchmail 6.2.0-3.el3.4, seamonkey 1.0.9-0.1.el3, seamonkey-nss 1.0.9-0.1.el3, seamonkey-chat 1.0.9-0.1.el3, +4 more Red Hat Enterprise Linux (v. 5 server) ruby 1.8.5-5.el5_3.7, mutt 1.4.2.2-3.0.2.el5, ruby-ri 1.8.5-5.el5_3.7, ruby-irb 1.8.5-5.el5_3.7, fetchmail 6.3.6-1.0.1.el5, ruby-libs 1.8.5-5.el5_3.7, +4 more Red Hat Enterprise Linux AS (Advanced Server) version 2.1 seamonkey 1.0.9-0.1.el2, seamonkey-nss 1.0.9-0.1.el2, seamonkey-chat 1.0.9-0.1.el2, seamonkey-mail 1.0.9-0.1.el2, seamonkey-nspr 1.0.9-0.1.el2, fetchmail 5.9.0-21.7.3.el2.1.6, +3 more Red Hat Enterprise Linux AS version 3 mutt 1.4.1-5.el3, evolution 1.4.5-20.el3, fetchmail 6.2.0-3.el3.4, seamonkey 1.0.9-0.1.el3, seamonkey-nss 1.0.9-0.1.el3, seamonkey-chat 1.0.9-0.1.el3, +4 more Red Hat Enterprise Linux AS version 4 irb 1.8.1-7.el4_8.3, devhelp 0.10-0.8.el4, ruby 1.8.1-7.el4_8.3, mutt 1.4.1-12.0.3.el4, seamonkey 1.0.9-2.el4, fetchmail 6.2.5-6.0.1.el4, +9 more
    fixed: vendor fix RHSA-2007:0385
  • Red Hat Enterprise Linux Desktop (v. 5 client) ruby 1.8.5-5.el5_3.7, mutt 1.4.2.2-3.0.2.el5, ruby-ri 1.8.5-5.el5_3.7, ruby-irb 1.8.5-5.el5_3.7, ruby-libs 1.8.5-5.el5_3.7, ruby-mode 1.8.5-5.el5_3.7, +4 more
    fixed: vendor fix RHSA-2007:0386
  • Red Hat Enterprise Linux Desktop version 4 irb 1.8.1-7.el4_8.3, devhelp 0.10-0.8.el4, ruby 1.8.1-7.el4_8.3, mutt 1.4.1-12.0.3.el4, seamonkey 1.0.9-2.el4, fetchmail 6.2.5-6.0.1.el4, +9 more Red Hat Enterprise Linux Desktop Workstation (v. 5 client) ruby 1.8.5-5.el5_3.7, ruby-ri 1.8.5-5.el5_3.7, ruby-irb 1.8.5-5.el5_3.7, fetchmail 6.3.6-1.0.1.el5, ruby-libs 1.8.5-5.el5_3.7, ruby-mode 1.8.5-5.el5_3.7, +3 more Red Hat Enterprise Linux ES version 2.1 seamonkey 1.0.9-0.1.el2, seamonkey-nss 1.0.9-0.1.el2, seamonkey-chat 1.0.9-0.1.el2, seamonkey-mail 1.0.9-0.1.el2, seamonkey-nspr 1.0.9-0.1.el2, fetchmail 5.9.0-21.7.3.el2.1.6, +3 more Red Hat Enterprise Linux ES version 3 mutt 1.4.1-5.el3, evolution 1.4.5-20.el3, fetchmail 6.2.0-3.el3.4, seamonkey 1.0.9-0.1.el3, seamonkey-nss 1.0.9-0.1.el3, seamonkey-chat 1.0.9-0.1.el3, +4 more Red Hat Enterprise Linux ES version 4 irb 1.8.1-7.el4_8.3, devhelp 0.10-0.8.el4, ruby 1.8.1-7.el4_8.3, mutt 1.4.1-12.0.3.el4, seamonkey 1.0.9-2.el4, fetchmail 6.2.5-6.0.1.el4, +9 more
    fixed: vendor fix RHSA-2007:0385
  • Red Hat Enterprise Linux Optional Productivity Applications (v. 5 server) thunderbird 1.5.0.12-1.el5
    fixed: vendor fix RHSA-2007:0401
  • Red Hat Enterprise Linux WS version 2.1 seamonkey 1.0.9-0.1.el2, seamonkey-nss 1.0.9-0.1.el2, seamonkey-chat 1.0.9-0.1.el2, seamonkey-mail 1.0.9-0.1.el2, seamonkey-nspr 1.0.9-0.1.el2, fetchmail 5.9.0-21.7.3.el2.1.6, +3 more Red Hat Enterprise Linux WS version 3 mutt 1.4.1-5.el3, evolution 1.4.5-20.el3, fetchmail 6.2.0-3.el3.4, seamonkey 1.0.9-0.1.el3, seamonkey-nss 1.0.9-0.1.el3, seamonkey-chat 1.0.9-0.1.el3, +4 more Red Hat Enterprise Linux WS version 4 irb 1.8.1-7.el4_8.3, devhelp 0.10-0.8.el4, ruby 1.8.1-7.el4_8.3, mutt 1.4.1-12.0.3.el4, seamonkey 1.0.9-2.el4, fetchmail 6.2.5-6.0.1.el4, +9 more Red Hat Linux Advanced Workstation 2.1 seamonkey 1.0.9-0.1.el2, seamonkey-nss 1.0.9-0.1.el2, seamonkey-chat 1.0.9-0.1.el2, seamonkey-mail 1.0.9-0.1.el2, seamonkey-nspr 1.0.9-0.1.el2, fetchmail 5.9.0-21.7.3.el2.1.6, +3 more
    fixed: vendor fix RHSA-2007:0385

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

2.42% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 2.0 2.6 AV:N/AC:H/Au:N/C:P/I:N/A:N

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.