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Fencer Vulns
medium 4.8

CVE-2021-33515 json

The submission service in Dovecot before 2.3.15 allows STARTTLS command injection in lib-smtp.

published 2021-06-28 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-20207

cvss
4.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.9%
EPSS 2.9% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

The submission service in Dovecot before 2.3.15 allows STARTTLS command injection in lib-smtp. Sensitive information can be redirected to an attacker-controlled address.

Patch / fix

  • dovecot dovecot 2.3.14.1
  • dovecot Debian 14, Debian 13, Debian 12 1:2.3.13+dfsg1-2

debian advisories DEBIAN-CVE-2021-33515

  • dovecot Ubuntu 20.04 LTS 1:2.3.7.2-1ubuntu3.4

ubuntu advisories UBUNTU-CVE-2021-33515

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 1:2.3.16-2.el8
  • dovecot-mysql RHEL 8 1:2.3.16-2.el8
  • dovecot-pgsql RHEL 8 1:2.3.16-2.el8
  • dovecot-pigeonhole RHEL 8 1:2.3.16-2.el8

red hat advisories RHSA-2022:1950

  • dovecot23 SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +6 more 2.3.11.3-24.1
  • dovecot23 SLE Module for Server Applications 15 SP3, SLE Module for Server Applications 15 SP2 2.3.11.3-55.1
  • dovecot23 SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 2.3.11.3-4.35.1

suse advisories SUSE-SU-2021:2124-1SUSE-SU-2021:2123-1SUSE-SU-2021:2122-1

  • dovecot24 openSUSE Tumbleweed 2.4.0-1.1
  • dovecot23 openSUSE Tumbleweed 2.3.16-1.6
  • dovecot23 openSUSE Leap 15.3 2.3.11.3-55.1
  • dovecot23 openSUSE Leap 15.2 2.3.11.3-lp152.2.9.1

opensuse advisories openSUSE-SU-2025:14715-1openSUSE-SU-2024:10726-1openSUSE-SU-2021:2123-1openSUSE-SU-2021:0920-1

  • dovecot AlmaLinux 8 1:2.3.16-2.el8
  • dovecot-mysql AlmaLinux 8 1:2.3.16-2.el8
  • dovecot-pgsql AlmaLinux 8 1:2.3.16-2.el8
  • dovecot-pigeonhole AlmaLinux 8 1:2.3.16-2.el8

almalinux advisories ALSA-2022:1950

  • dovecot Rocky Linux 8 1:2.3.16-2.el8

rocky linux advisories RLSA-2022:1950

  • dovecot Alpine 3.24, Alpine 3.23, Alpine 3.22 +11 more 2.3.15-r0

alpine advisories ALPINE-CVE-2021-33515

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 CBL-Mariner 2.0 2.3.20-1

azure linux advisories AZL-7196

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • dovecot Arch Linux 2.3.15-1

arch linux advisories AVG-2087

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-2021-33515 updated cvss 4.2

dovecot: plaintext commands injection

  • Red Hat Enterprise Linux 6 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 9 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole
    affected: no fix available
  • Red Hat Enterprise Linux AppStream (v. 8) dovecot 2.3.16-2.el8, dovecot-mysql 2.3.16-2.el8, dovecot-pgsql 2.3.16-2.el8, dovecot-pigeonhole 2.3.16-2.el8 Red Hat Enterprise Linux CRB (v. 8) dovecot 2.3.16-2.el8
    fixed: vendor fix RHSA-2022:1950
  • 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

2.85% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD 2.0 5.8 AV:N/AC:M/Au:N/C:P/I:P/A:N

Classification

Weakness
  • CWE-77 Improper Neutralization of Special Elements used in a Command

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.