CVE-2026-44786: Discourse is an open-source discussion platform

Routine

HIGH 7.5REMOTEUPGRADE

CVE-2026-44786 is a high-severity flaw (CVSS 7.5) affecting discourse. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.4, 2026.3.0-latest to before 2026.3.1, and 2026.4.0-latest to before 2026.4.1, chat events for public category channels are published to MessageBus without permission scoping, so any MessageBus subscriber without chat enabled could receive chat message payloads in real time. This issue has been patched in versions 2026.1.4, 2026.3.1, 2026.4.1, and 2026

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 83%)
CISA exploited list	No
Weakness	CWE-200
Published	2026-06-12
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: discourse

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

Am I affected?

Timeline

2026-06-12 21:16 UTCPublished CVE record published
2026-06-17 18:46 UTCUpdated Record last modified

discourse discourse UPGRADE

Affected: < 2026.1.0 · >= 2026.1.0 and < 2026.1.4 · >= 2026.3.0 and < 2026.3.1 · >= 2026.4.0 and < 2026.4.1 · 2026.5.0

Fixed in: 2026.1.0, 2026.1.4, 2026.3.1, 2026.4.1

Safe to downgrade to: a release before 2026.1.0

1. Check installed version

apt-cache policy discourse || rpm -q discourse || discourse --version

2. UPGRADE to 2026.1.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade discourse

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade discourse

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 2026.1.0 (Debian / Ubuntu)

apt-cache madison discourse sudo apt install discourse=<VERSION_BEFORE_2026.1.0> sudo apt-mark hold discourse

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list discourse sudo dnf downgrade discourse-<VERSION_BEFORE_2026.1.0> sudo dnf versionlock add discourse

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.

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-2026-44786?

discourse: upgrade to 2026.1.0, 2026.1.4, 2026.3.1, 2026.4.1. Exact commands for each OS are on this page.

Is CVE-2026-44786 being exploited?

CVE-2026-44786 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-2026-44786 affect?

CVE-2026-44786 affects discourse. Severity is high (CVSS 7.5). Discourse is an open-source discussion platform. From versions 2026.1.0-latest to before 2026.1.4, 2026.3.0-latest to before 2026.3.1, and 2026.4.0-latest to before 2026.4.1, chat events for public category channels are published to Message

How urgent is CVE-2026-44786?

Priority 36/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-44780 MEDIUM 4.3 UPGRADE Discourse is an open-source discussion platform
CVE-2026-44782 MEDIUM 4.3 UPGRADE Discourse is an open-source discussion platform
CVE-2026-44783 MEDIUM 5.4 UPGRADE Discourse is an open-source discussion platform
CVE-2026-44784 MEDIUM 6.5 UPGRADE Discourse is an open-source discussion platform
CVE-2026-44785 MEDIUM 4.3 UPGRADE Discourse is an open-source discussion platform

References

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