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Fencer Vulns
medium 5.3

CVE-2020-10958 json

In Dovecot before 2.3.10.1, a crafted SMTP/LMTP message triggers an unauthenticated use-after-free bug in submission-login, submission, or…

published 2020-05-18 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-3362

cvss
5.3
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
6.1%
EPSS 6.1% chance of exploitation in 30 days, percentile 93%
public exploits
0
none known

Summary

In Dovecot before 2.3.10.1, a crafted SMTP/LMTP message triggers an unauthenticated use-after-free bug in submission-login, submission, or lmtp, and can lead to a crash under circumstances involving many newlines after a command.

Patch / fix

  • dovecot dovecot 2.3.10.1
  • dovecot Debian 14, Debian 13, Debian 12 1:2.3.10.1+dfsg1-1

debian advisories DEBIAN-CVE-2020-10958

  • dovecot Ubuntu 20.04 LTS 1:2.3.7.2-1ubuntu3.1

ubuntu advisories UBUNTU-CVE-2020-10958

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

  • dovecot RHEL 8 1:2.3.8-4.el8
  • dovecot-mysql RHEL 8 1:2.3.8-4.el8
  • dovecot-pgsql RHEL 8 1:2.3.8-4.el8
  • dovecot-pigeonhole RHEL 8 1:2.3.8-4.el8

red hat advisories RHSA-2020:4763

  • dovecot23 SLE Module for Server Applications 15 SP1 2.3.10-11.1
  • dovecot23 SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 2.3.10-4.22.1

suse advisories SUSE-SU-2020:1380-1SUSE-SU-2020:1379-1

  • dovecot24 openSUSE Tumbleweed 2.4.0-1.1
  • dovecot23 openSUSE Tumbleweed 2.3.16-1.6
  • dovecot23 openSUSE Leap 15.1 2.3.10-lp151.2.9.1

opensuse advisories openSUSE-SU-2025:14715-1openSUSE-SU-2024:10726-1openSUSE-SU-2020:0720-1

  • dovecot AlmaLinux 8 1:2.3.8-4.el8

almalinux advisories ALSA-2020:4763

  • dovecot Alpine 3.24, Alpine 3.23, Alpine 3.22 +14 more 2.3.10.1-r0

alpine advisories ALPINE-CVE-2020-10958

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

  • dovecot Arch Linux 2.3.10.1-1

arch linux advisories AVG-1162

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-2020-10958 updated cvss 5.9

dovecot: command followed by sufficient number of newlines leads to use-after-free

  • Red Hat CodeReady Linux Builder (v. 8) dovecot 2.3.8-4.el8 Red Hat Enterprise Linux AppStream (v. 8) dovecot 2.3.8-4.el8, dovecot-mysql 2.3.8-4.el8, dovecot-pgsql 2.3.8-4.el8, dovecot-pigeonhole 2.3.8-4.el8
    fixed: vendor fix RHSA-2020:4763
  • Red Hat Enterprise Linux 5 dovecot Red Hat Enterprise Linux 6 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole Red Hat Enterprise Linux 7 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole
    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

6.12% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • seclists.org http://seclists.org/fulldisclosure/2020/May/37 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 5.3 CVSS:3.0/AC:L/AV:N/A:L/C:N/I:N/PR:N/S:U/UI:N
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CNA 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

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.