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Fencer Vulns
medium 5.3

CVE-2020-28896 json

Mutt before 2.0.2 and NeoMutt before 2020-11-20 did not ensure that $ssl_force_tls was processed if an IMAP server's initial server respons…

published 2020-11-23 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-21287

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

Mutt before 2.0.2 and NeoMutt before 2020-11-20 did not ensure that $ssl_force_tls was processed if an IMAP server's initial server response was invalid. The connection was not properly closed, and the code could continue attempting to authenticate. This could result in authentication credentials being exposed on an unencrypted connection, or to a machine-in-the-middle.

Patch / fix

  • mutt mutt 2.0.2
  • neomutt neomutt 2020-11-20
  • mutt Debian 14, Debian 13, Debian 12 2.0.2-1
  • neomutt Debian 14, Debian 13, Debian 12 20201120+dfsg.1-1

debian advisories DEBIAN-CVE-2020-28896

  • mutt Ubuntu 16.04 LTS 1.5.24-1ubuntu0.5
  • mutt Ubuntu 18.04 LTS 1.9.4-3ubuntu0.4
  • mutt Ubuntu 20.04 LTS 1.13.2-1ubuntu0.3
  • neomutt Ubuntu Pro 18.04 LTS 20171215+dfsg.1-1ubuntu0.1~esm1
  • neomutt Ubuntu Pro 20.04 LTS 20191207+dfsg.1-1.1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2020-28896

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • mutt RHEL 8 5:2.0.7-1.el8

red hat advisories RHSA-2021:4181

  • mutt SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +14 more 1.10.1-55.18.1
  • mutt SLES for SAP 15, SLES 15-LTSS, SLE Module for Basesystem 15 SP2 +3 more 1.10.1-3.11.1
  • mutt SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 1.5.17-42.56.1

suse advisories SUSE-SU-2020:3632-1SUSE-SU-2020:3568-1SUSE-SU-2020:14551-1

  • mutt openSUSE Tumbleweed 2.0.7-2.2
  • neomutt openSUSE Tumbleweed 20210205-3.3
  • neomutt Package Hub 15 SP2 20201120-bp152.2.3.1
  • neomutt Package Hub 15 SP1 20201120-bp151.3.3.1
  • mutt openSUSE Leap 15.2 1.10.1-lp152.3.6.1
  • mutt openSUSE Leap 15.1 1.10.1-lp151.2.6.1
  • neomutt openSUSE Leap 15.2, openSUSE Leap 15.1 20201120-lp152.2.3.1

opensuse advisories openSUSE-SU-2024:11069-1openSUSE-SU-2024:11079-1openSUSE-SU-2020:2158-1openSUSE-SU-2020:2157-1openSUSE-SU-2020:2141-1openSUSE-SU-2020:2128-1

  • mutt AlmaLinux 8 5:2.0.7-1.el8

almalinux advisories ALSA-2021:4181

  • mutt Rocky Linux 8 5:2.0.7-1.el8

rocky linux advisories RLSA-2021:4181

  • mutt Alpine 3.24, Alpine 3.23, Alpine 3.22 +9 more 2.0.2-r0

alpine advisories ALPINE-CVE-2020-28896

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • mutt Arch Linux 2.0.2-1
  • neomutt Arch Linux 20201120-1

arch linux advisories AVG-1288AVG-1289

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-2020-28896 updated cvss 5.3

mutt: Incorrect handling of invalid initial IMAP responses could lead to an authentication attempt over unencrypted connection

  • Red Hat Enterprise Linux 5 mutt Red Hat Enterprise Linux 6 mutt Red Hat Enterprise Linux 7 mutt
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) mutt 2.0.7-1.el8
    fixed: vendor fix RHSA-2021:4181
  • Red Hat Enterprise Linux 9 mutt
    not affected: vulnerable code not present

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

2.35% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
NVD 2.0 2.6 AV:N/AC:H/Au:N/C:P/I:N/A:N

Classification

Weakness
  • CWE-287 Improper Authentication
  • CWE-755 Improper Handling of Exceptional Conditions

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.