CVE-2023-40588: Discourse DoS via 2FA and Security Key Names

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-09-15 · updated 2026-06-17
Weakness: CWE-770

Description

Discourse is an open-source discussion platform. Prior to version 3.1.1 of the `stable` branch and version 3.2.0.beta1 of the `beta` and `tests-passed` branches, a malicious user could add a 2FA or security key with a carefully crafted name to their account and cause a denial of service for other users. The issue is patched in version 3.1.1 of the `stable` branch and version 3.2.0.beta1 of the `beta` and `tests-passed` branches. There are no known workarounds.

Affected products

discourse: before 3.1.1; 1.1.0-beta1, 1.1.0-beta2, 1.1.0-beta3, 1.1.0-beta4, 1.1.0-beta5, 1.1.0-beta6 (+207) — fixed in 3.1.1

How to fix

Upgrade to a fixed version: discourse 3.1.1. Check the vendor advisory for mitigations.

References

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