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Fencer Vulns
medium 5.9

CVE-2020-14954 json

Mutt before 1.14.4 and NeoMutt before 2020-06-19 have a STARTTLS buffering issue that affects IMAP, SMTP, and POP3.

published 2020-06-21 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-7089

cvss
5.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.3%
EPSS 2.3% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

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."

Patch / fix

  • mutt mutt 1.14.4
  • neomutt neomutt 20200619
  • mutt Debian 14, Debian 13, Debian 12 1.14.4-1
  • neomutt Debian 14, Debian 13, Debian 12 20200619+dfsg.1-1

debian advisories DEBIAN-CVE-2020-14954

  • mutt Ubuntu 16.04 LTS 1.5.24-1ubuntu0.4
  • mutt Ubuntu 18.04 LTS 1.9.4-3ubuntu0.3
  • mutt Ubuntu 20.04 LTS 1.13.2-1ubuntu0.2
  • 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-2020-14954

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 SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 1.5.17-42.51.1
  • mutt SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +12 more 1.10.1-55.11.1
  • mutt SLES for SAP 15, SLES 15-LTSS, SLE Module for Basesystem 15 SP2 +3 more 1.10.1-3.8.1

suse advisories SUSE-SU-2020:14414-1SUSE-SU-2020:1794-1SUSE-SU-2020:1771-1

  • 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
  • neomutt openSUSE Leap 15.2, openSUSE Leap 15.1 20201120-lp152.2.3.1
  • mutt openSUSE Leap 15.2 1.10.1-lp152.3.3.1
  • mutt openSUSE Leap 15.1 1.10.1-lp151.2.3.1

opensuse advisories openSUSE-SU-2024:11069-1openSUSE-SU-2024:11079-1openSUSE-SU-2020:2158-1openSUSE-SU-2020:2157-1openSUSE-SU-2020:2127-1openSUSE-SU-2020:0915-1

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-2020-14954 updated cvss 7.4

mutt: response Injection via STARTTLS in SMTP, POP3 and IMAP

  • Red Hat Enterprise Linux 5 mutt Red Hat Enterprise Linux 6 mutt
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 mutt Red Hat Enterprise Linux 8 mutt
    affected: no fix planned “Will not fix”

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

2.31% 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 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component

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.