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No exploitation reportedFix available

CVE-2020-12100

No exploitation reported by the sources we read.

  • Published2020-08-12
  • Fixed in2.3.11.3
  • WeaknessCWE-674

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2020-08-1216:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 15:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-12100?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-12100?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Dovecot
BranchAffectedFixed in
2.3< 2.3.11.32.3.11.3
Canonical ubuntu linux
BranchAffectedFixed in
14.4= 14.04no fix published
16.4= 16.04no fix published
18.4= 18.04no fix published
20.4= 20.04no fix published
Fedoraproject fedora
BranchAffectedFixed in
31.x= 31no fix published
32.x= 32no fix published
33.x= 33no fix published

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • dovecotUbuntu:Pro:14.04:LTSall versions · fixed in 1:2.2.9-1ubuntu2.6+esm3
  • dovecotUbuntu:20.04:LTSall versions · fixed in 1:2.3.7.2-1ubuntu3.2
  • dovecotUbuntu:18.04:LTSall versions · fixed in 1:2.2.33.2-1ubuntu4.6
  • dovecotUbuntu:16.04:LTSall versions · fixed in 1:2.2.22-1ubuntu2.13
  • dovecotTuxCare:OracleLinux:6all versions · fixed in 1:2.0.9-23.el6.cloudlinux.elsand 4 other packages
  • dovecotTuxCare:CentOS:6all versions · fixed in 1:2.0.9-23.el6.cloudlinux.elsand 4 other packages
  • dovecotRed Hat:rhel_eus:8.1::crball versions · fixed in 1:2.2.36-10.el8_1.2and 6 other packages
  • dovecotRed Hat:rhel_eus:8.1::appstreamall versions · fixed in 1:2.2.36-10.el8_1.2and 8 other packages

35 more package ranges on OSV.dev

Vendor advisories

  • CVE-2020-12100 Red Hat Product Security333 products fixed · 6 known affected

    dovecot: Resource exhaustion via deeply nested MIME parts

    dovecot as a component of Red Hat Enterprise Linux 6 · dovecot-devel as a component of Red Hat Enterprise Linux 6 · dovecot-mysql as a component of Red Hat Enterprise Linux 6 · +3 more

  • RHSA-2020:3736 Red Hat Product Security68 products fixed

    Red Hat Security Advisory: dovecot security update

  • RHSA-2020:3735 Red Hat Product Security17 products fixed

    Red Hat Security Advisory: dovecot security update

  • RHSA-2020:3713 Red Hat Product Security68 products fixed

    Red Hat Security Advisory: dovecot security update

  • RHSA-2020:3617 Red Hat Product Security45 products fixed

    Red Hat Security Advisory: dovecot security update

Full record on NVD

Fix

  1. Update Dovecot to 2.3.11.3
  2. Vendor fix Red Hat Product Security RHSA-2020:3736 · 68 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  3. Workaround from the vendor Red Hat Product Security RHSA-2020:3736 · 68 productsUpstream suggests that this flaw can be mitigated by limiting MIME structures in MTA
  4. No fix available, says the vendor Red Hat Product Security CVE-2020-12100 · 6 productsAffected

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • NVDweakness (CWE)CWE-674read 2026-10-23
  • FIRST EPSSEPSS score5.3 %2026-11-03
  • OSVaffected packages—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2020-08-12
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-12100?

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.

Is CVE-2020-12100 actively exploited?

Active exploitation of CVE-2020-12100 has not been confirmed. Its EPSS score was 5.3% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-12100?

CVE-2020-12100 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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