CVE-2023-46130: Bypassing height value allowed in some theme components

Severity: medium (CVSS 5.4 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: 2023-11-10 · updated 2026-06-17
Weakness: CWE-770

Description

Discourse is an open source platform for community discussion. Prior to version 3.1.3 of the `stable` branch and version 3.2.0.beta3 of the `beta` and `tests-passed` branches, some theme components allow users to add svgs with unlimited `height` attributes, and this can affect the availability of subsequent replies in a topic. Most Discourse instances are unaffected, only instances with the svgbob or the mermaid theme component are within scope. The issue is patched in version 3.1.3 of the `stable` branch and version 3.2.0.beta3 of the `beta` and `tests-passed` branches. As a workaround, disable or remove the relevant theme components.

Affected products

discourse: before 3.1.3; before 3.2.0; 3.2.0-beta1, 3.2.0-beta2 — fixed in 3.1.3, 3.2.0

How to fix

Upgrade to a fixed version: discourse 3.1.3, 3.2.0. Check the vendor advisory for mitigations.

References

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