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Fencer Vulns
high 7.5

CVE-2020-12100 json

In Dovecot before 2.3.11.3, uncontrolled recursion in submission, lmtp, and lda allows remote attackers to cause a denial of service (resou…

published 2020-08-12 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-4416

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
5.3%
EPSS 5.3% chance of exploitation in 30 days, percentile 92%
public exploits
0
none known

Summary

In Dovecot before 2.3.11.3, uncontrolled recursion in submission, lmtp, and lda allows remote attackers to cause a denial of service (resource consumption) via a crafted e-mail message with deeply nested MIME parts.

Patch / fix

  • dovecot dovecot 2.3.11.3
  • dovecot Debian 14, Debian 13, Debian 12 1:2.3.11.3+dfsg1-1

debian advisories DEBIAN-CVE-2020-12100

  • dovecot Ubuntu 16.04 LTS 1:2.2.22-1ubuntu2.13
  • dovecot Ubuntu 18.04 LTS 1:2.2.33.2-1ubuntu4.6
  • dovecot Ubuntu 20.04 LTS 1:2.3.7.2-1ubuntu3.2
  • dovecot Ubuntu Pro 14.04 LTS 1:2.2.9-1ubuntu2.6+esm3

ubuntu advisories UBUNTU-CVE-2020-12100

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 1:2.3.8-2.el8_2.2
  • dovecot-mysql RHEL 8 1:2.3.8-2.el8_2.2
  • dovecot-pgsql RHEL 8 1:2.3.8-2.el8_2.2
  • dovecot-pigeonhole RHEL 8 1:2.3.8-2.el8_2.2
  • dovecot RHEL 7 1:2.2.36-6.el7_8.1
  • dovecot-mysql RHEL 7 1:2.2.36-6.el7_8.1
  • dovecot-pgsql RHEL 7 1:2.2.36-6.el7_8.1
  • dovecot-pigeonhole RHEL 7 1:2.2.36-6.el7_8.1

red hat advisories RHSA-2020:3736RHSA-2020:3735RHSA-2020:3713RHSA-2020:3617

  • dovecot23 SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 2.3.11.3-4.32.1
  • dovecot23 SLE Module for Server Applications 15 SP2 2.3.11.3-17.5.1
  • dovecot23 SLE Module for Server Applications 15 SP1 2.3.11.3-21.1

suse advisories SUSE-SU-2021:0029-1SUSE-SU-2021:0028-1SUSE-SU-2021:0027-1

  • dovecot24 openSUSE Tumbleweed 2.4.0-1.1
  • dovecot23 openSUSE Tumbleweed 2.3.16-1.6
  • dovecot23 openSUSE Leap 15.1 2.3.11.3-lp151.2.15.1
  • dovecot23 openSUSE Leap 15.2 2.3.11.3-lp152.2.6.1

opensuse advisories openSUSE-SU-2025:14715-1openSUSE-SU-2024:10726-1openSUSE-SU-2021:0072-1openSUSE-SU-2021:0026-1

  • dovecot Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 2.3.11.3-r0

alpine advisories ALPINE-CVE-2020-12100

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

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-2020-12100 updated cvss 7.5

dovecot: Resource exhaustion via deeply nested MIME parts

  • Red Hat Enterprise Linux 6 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole
    affected: workaround, no fix available “Upstream suggests that this flaw can be mitigated by limiting MIME structures in MTA”
  • Red Hat CodeReady Linux Builder (v. 8) dovecot 2.3.8-2.el8_2.2
    fixed: vendor fix “Upstream suggests that this flaw can be mitigated by limiting MIME structures in MTA” RHSA-2020:3713
  • Red Hat CodeReady Linux Builder EUS (v. 8.1) dovecot 2.2.36-10.el8_1.2
    fixed: vendor fix “Upstream suggests that this flaw can be mitigated by limiting MIME structures in MTA” RHSA-2020:3736
  • Red Hat Enterprise Linux AppStream (v. 8) dovecot 2.3.8-2.el8_2.2, dovecot-mysql 2.3.8-2.el8_2.2, dovecot-pgsql 2.3.8-2.el8_2.2, dovecot-pigeonhole 2.3.8-2.el8_2.2
    fixed: vendor fix “Upstream suggests that this flaw can be mitigated by limiting MIME structures in MTA” RHSA-2020:3713
  • Red Hat Enterprise Linux AppStream E4S (v. 8.0) dovecot 2.2.36-5.el8_0.3, dovecot-mysql 2.2.36-5.el8_0.3, dovecot-pgsql 2.2.36-5.el8_0.3
    fixed: vendor fix “Upstream suggests that this flaw can be mitigated by limiting MIME structures in MTA” RHSA-2020:3735
  • Red Hat Enterprise Linux AppStream EUS (v. 8.1) dovecot 2.2.36-10.el8_1.2, dovecot-mysql 2.2.36-10.el8_1.2, dovecot-pgsql 2.2.36-10.el8_1.2, dovecot-pigeonhole 2.2.36-10.el8_1.2
    fixed: vendor fix “Upstream suggests that this flaw can be mitigated by limiting MIME structures in MTA” RHSA-2020:3736
  • Red Hat Enterprise Linux Server (v. 7) dovecot 2.2.36-6.el7_8.1, dovecot-mysql 2.2.36-6.el7_8.1, dovecot-pgsql 2.2.36-6.el7_8.1, dovecot-pigeonhole 2.2.36-6.el7_8.1 Red Hat Enterprise Linux Server Optional (v. 7) dovecot-devel 2.2.36-6.el7_8.1, dovecot-debuginfo 2.2.36-6.el7_8.1 Red Hat Enterprise Linux Workstation (v. 7) dovecot 2.2.36-6.el7_8.1, dovecot-mysql 2.2.36-6.el7_8.1, dovecot-pgsql 2.2.36-6.el7_8.1, dovecot-pigeonhole 2.2.36-6.el7_8.1 Red Hat Enterprise Linux Workstation Optional (v. 7) dovecot-devel 2.2.36-6.el7_8.1, dovecot-debuginfo 2.2.36-6.el7_8.1
    fixed: vendor fix “Upstream suggests that this flaw can be mitigated by limiting MIME structures in MTA” RHSA-2020:3617
  • Red Hat Enterprise Linux 5 dovecot
    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

5.26% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • openwall.com http://www.openwall.com/lists/oss-security/2020/08/12/1 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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.