CVE-2020-28896

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.

Published: 2020-11-23 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-28896 is rated Low Risk (30.3/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.10%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-28896

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-02-23 0.33% 0.10% -0.24%
2 2025-12-28 0.38% 0.33% -0.05%
3 2025-12-27 — 0.38% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-28896

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.6 3.6 [email protected]
2.6 2.0 LOW
AV:N/AC:H/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:H)
Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 4.9 2.9 [email protected]

Weakness enumeration for CVE-2020-28896

OS Trackers for CVE-2020-28896

vendor priority summary link
alpine medium CVE-2020-28896: 1 source package rows (mutt); 9 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 2. https://security.alpinelinux.org/vuln/CVE-2020-28896
debian not yet assigned CVE-2020-28896 not yet assigned priority: Debian including 2 source packages (mutt, neomutt), 10 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 10. https://security-tracker.debian.org/tracker/CVE-2020-28896
gentoo normal CVE-2020-28896: 1 GLSA(s) (202101-32), 2 atom(s) (mail-client/mutt, mail-client/neomutt); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-28896
redhat medium — https://access.redhat.com/security/cve/CVE-2020-28896
suse medium CVE-2020-28896 severity moderate: SUSE including 267 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 327 product×package rows across 54 product lines (HPE Helion OpenStack 8, Image SLES12-SP5-Azure-SAP-BYOS, … (54 product lines)): Known Affected 231, Fixed 96. https://www.suse.com/security/cve/CVE-2020-28896/
ubuntu medium CVE-2020-28896 medium priority: Ubuntu including 2 source packages (mutt, neomutt), 30 status rows across 15 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 18, released 8, DNE 3, ignored 1. https://ubuntu.com/security/CVE-2020-28896

Affected software / configurations for CVE-2020-28896

Vendor Product Version Raw CPE
mutt mutt < 2.0.2 cpe:2.3:a:mutt:mutt:*:*:*:*:*:*:*:*
neomutt neomutt < 2020-11-20 cpe:2.3:a:neomutt:neomutt:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

References for CVE-2020-28896

cvelogic Threat Intelligence