CVE-2023-38498: Discourse vulnerable to DoS via defer queue

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-07-28 · updated 2026-06-17
Weakness: CWE-400

Description

Discourse is an open source discussion platform. Prior to version 3.0.6 of the `stable` branch and version 3.1.0.beta7 of the `beta` and `tests-passed` branches, a malicious user can prevent the defer queue from proceeding promptly on sites hosted in the same multisite installation. The issue is patched in version 3.0.6 of the `stable` branch and version 3.1.0.beta7 of the `beta` and `tests-passed` branches. There are no known workarounds for this vulnerability. Users of multisite configurations should upgrade.

Affected products

discourse: before 3.0.6; 1.1.0-beta1, 1.1.0-beta2, 1.1.0-beta3, 1.1.0-beta4, 1.1.0-beta5, 1.1.0-beta6 (+205) — fixed in 3.0.6

How to fix

Upgrade to a fixed version: discourse 3.0.6. Check the vendor advisory for mitigations.

References

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