Free and open · new CVEs checked every 20 minutesStatusRSSOpen dataContact

CVE-2019-11500: In Dovecot before 2.2.36.4 and 2.3.x before 2.3.7.2 (and Pigeonhole before 0.5.7.2), protocol processing can f

74
This week
CRITICAL 9.8REMOTEWATCHLISTUPGRADEUPGRADEMITIGATE

CVE-2019-11500 is a critical-severity flaw (CVSS 9.8) affecting dovecot, pigeonhole, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In Dovecot before 2.2.36.4 and 2.3.x before 2.3.7.2 (and Pigeonhole before 0.5.7.2), protocol processing can fail for quoted strings. This occurs because '\0' characters are mishandled, and can lead to out-of-bounds writes and remote code execution.

Why this priority

  • Critical severity
  • EPSS top 1%: very likely to be exploited
  • Public exploit reference
  • Remotely exploitable, no login, no user action
  • On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score9.8 (Critical)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededNone
User interactionNone
EPSS exploit chance62.3% (top 1%)
CISA exploited listNo
WeaknessCWE-787
Published2019-08-29
Last modified2026-06-17
Publisher (CNA): MITRE · Vendor: debian · dovecot · fedoraproject

Share: LinkedIn · X · Reddit

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

dovecot dovecot UPGRADE
Affected: < 2.2.36.4 · >= 2.3.0 and < 2.3.7.2
Fixed in: 2.2.36.4, 2.3.7.2
Safe to downgrade to: a release before 2.3.0
1. Check installed version
apt-cache policy dovecot || rpm -q dovecot || dovecot --version
2. UPGRADE to 2.2.36.4 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade dovecot
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade dovecot
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 2.3.0 (Debian / Ubuntu)
apt-cache madison dovecot sudo apt install dovecot=<VERSION_BEFORE_2.3.0> sudo apt-mark hold dovecot
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list dovecot sudo dnf downgrade dovecot-<VERSION_BEFORE_2.3.0> sudo dnf versionlock add dovecot
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
dovecot pigeonhole UPGRADE
Affected: < 0.5.7.2
Fixed in: 0.5.7.2
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy pigeonhole || rpm -q pigeonhole || pigeonhole --version
2. UPGRADE to 0.5.7.2 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade pigeonhole
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade pigeonhole
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
debian debian linux MITIGATE
Affected: 8.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 8.0
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
fedoraproject fedora MITIGATE
Affected: 30
Fixed in: no fixed release known
Safe to downgrade to: a release before 30
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.
Fedora 46 · root · FIXED · 6.40.04-7.fc46 · FEDORA-2026-7329868400 · source
sudo dnf upgrade --advisory=FEDORA-2026-7329868400
Debian 12 · dovecot · FIXED · 1:2.3.7.2-1
sudo apt update && sudo apt install --only-upgrade dovecot dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dovecot)" ge "1:2.3.7.2-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · dovecot · FIXED · 1:2.3.7.2-1
sudo apt update && sudo apt install --only-upgrade dovecot dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dovecot)" ge "1:2.3.7.2-1" && echo PATCHED || echo STILL-VULNERABLE
RHEL 6 · dovecot · FIXED · dovecot-2.0.9-22.el6_10.1
sudo dnf upgrade --advisory=RHSA-2019:2885 rpm -q dovecot
RHEL 7 · dovecot · FIXED · dovecot-2.2.36-3.el7_7.1
sudo dnf upgrade --advisory=RHSA-2019:2836 rpm -q dovecot
RHEL 8 · dovecot · FIXED · dovecot-2.2.36-5.el8_0.1
sudo dnf upgrade --advisory=RHSA-2019:2822 rpm -q dovecot
RHEL 5 · dovecot · DEFERRED
Alpine 3.20 · dovecot · FIXED · dovecot-2.3.7.2-r0
apk add --upgrade dovecot apk info -v dovecot
Alpine 3.21 · dovecot · FIXED · dovecot-2.3.7.2-r0
apk add --upgrade dovecot apk info -v dovecot
Alpine 3.22 · dovecot · FIXED · dovecot-2.3.7.2-r0
apk add --upgrade dovecot apk info -v dovecot
Alpine 3.23 · dovecot · FIXED · dovecot-2.3.7.2-r0
apk add --upgrade dovecot apk info -v dovecot
Amazon Linux 2 · see advisory · FIXED · ALAS2-2019-1347 · source
sudo yum update --advisory=ALAS2-2019-1347
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2019-11500?

dovecot: upgrade to 2.2.36.4, 2.3.7.2; pigeonhole: upgrade to 0.5.7.2; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-11500 being exploited?

CVE-2019-11500 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2019-11500 affect?

CVE-2019-11500 affects dovecot, pigeonhole, debian linux. Severity is critical (CVSS 9.8). In Dovecot before 2.2.36.4 and 2.3.x before 2.3.7.2 (and Pigeonhole before 0.5.7.2), protocol processing can fail for quoted strings. This occurs because '\0' characters are mishandled, and can lead to out-of-bounds writes and remote code e

How urgent is CVE-2019-11500?

Priority 74/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities · Dovecot vulnerabilities

Related CVEs

References

← Back to latest CVEs

Get the weekly exploited-CVE digest by emailThe CVEs being attacked this week and how to fix them. No spam, unsubscribe any time.