CVE-2020-14954

Mutt before 1.14.4 and NeoMutt before 2020-06-19 have a STARTTLS buffering issue that affects IMAP, SMTP, and POP3. When a server sends a "begin TLS" response, the client reads additional data (e.g., from a man-in-the-middle attacker) and evaluates it in a TLS context, aka "response injection."

Published: 2020-06-21 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-14954 is rated Moderate Risk (49.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.29%). Review affected assets and schedule remediation.

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-2020-14954

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 2026-06-15 4.79% 2.29% -2.50%
2 2026-05-13 5.78% 4.79% -0.99%
3 2026-02-24 — 5.78% —

Full EPSS history (30 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-14954

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/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:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2020-14954

OS Trackers for CVE-2020-14954

vendor priority summary link
debian not yet assigned CVE-2020-14954 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-2020-14954
gentoo normal CVE-2020-14954: 1 GLSA(s) (202007-57), 2 atom(s) (mail-client/mutt, mail-client/neomutt); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-14954
redhat medium — https://access.redhat.com/security/cve/CVE-2020-14954
suse high CVE-2020-14954 severity important: SUSE including 35 source package names (mutt-1.10.1-3.8.1, mutt-1.10.1-55.11.1, …), 92 product×package rows across 49 product lines (HPE Helion OpenStack 8, Image SLES12-SP5-Azure-SAP-BYOS, … (49 product lines)): Fixed 92. https://www.suse.com/security/cve/CVE-2020-14954/
ubuntu medium CVE-2020-14954 medium priority: Ubuntu including 2 source packages (mutt, neomutt), 32 status rows across 16 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 20, released 8, DNE 3, ignored 1. https://ubuntu.com/security/CVE-2020-14954

Affected software / configurations for CVE-2020-14954

Vendor Product Version Raw CPE
mutt mutt < 1.14.4 cpe:2.3:a:mutt:mutt:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
neomutt neomutt < 20200619 cpe:2.3:a:neomutt:neomutt:*:*:*:*:*:*:*:*
fedoraproject fedora 31 cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
canonical ubuntu_linux 12.04 cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:-:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 19.10 cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*
canonical ubuntu_linux 20.04 cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
opensuse leap 15.2 cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*

References for CVE-2020-14954

URL Tags
http://lists.mutt.org/pipermail/mutt-announce/Week-of-Mon-20200615/000023.html Mailing List Vendor Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00064.html Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00070.html Third Party Advisory
http://www.mutt.org/ Product
https://github.com/neomutt/neomutt/commit/fb013ec666759cb8a9e294347c7b4c1f597639cc Patch
https://github.com/neomutt/neomutt/releases/tag/20200619 Release Notes
https://gitlab.com/muttmua/mutt/-/commit/c547433cdf2e79191b15c6932c57f1472bfb5ff4 Patch
https://gitlab.com/muttmua/mutt/-/issues/248 Issue Tracking Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/06/msg00039.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/06/msg00040.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EFMEILCBKMZRRZDMUGWLVN4PQQ4VTAZE/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3LXFVPTLK4PNHL6MPKJNJQJ25CH7GLQ/
https://security.gentoo.org/glsa/202007-57 Third Party Advisory
https://usn.ubuntu.com/4403-1/ Third Party Advisory
https://www.debian.org/security/2020/dsa-4707 Third Party Advisory
https://www.debian.org/security/2020/dsa-4708 Third Party Advisory
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