Is CVE-2026-91119 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-91119 being exploited in the wild.

How severe is CVE-2026-91119?

Medium severity, with a CVSS score of 6.4, published 24 September 2026.

Which products and versions are affected?

Discourse Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.

Is there a fix for CVE-2026-91119?

A patch was published on 2026-08-25: Fix committed; patches released in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-91119 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-91119?

Check whether you run Discourse at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-91119: Discourse stored HTML injection in activity log components

CVE-2026-91119 · Severity: medium · CVSS 6.4 · Published 2026-09-24

Discourse, an open-source discussion platform, contains a vulnerability in how it renders user activity logs and topic actions. A user with a specially crafted display name containing quotes can inject malicious HTML code that executes when other users view the affected activity log or topic, potentially allowing session hijacking or data theft. This is a stored attack, meaning the malicious payload persists and affects all users who view the affected content.

Technologies: Discourse. Vendors: Discourse.

Quick answers

Is CVE-2026-91119 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-91119 being exploited in the wild.
How severe is CVE-2026-91119?: Medium severity, with a CVSS score of 6.4, published 24 September 2026.
Which products and versions are affected?: Discourse Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.
Is there a fix for CVE-2026-91119?: A patch was published on 2026-08-25: Fix committed; patches released in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-91119 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-91119?: Check whether you run Discourse at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability exists in the small-action and nested-activity-log components, which fail to URL-encode the action_code_who parameter before interpolating it into HTML href attributes. An attacker can terminate the intended URL attribute with a quote character and inject arbitrary HTML/JavaScript elements. While the visible mention text is properly escaped, the unencoded href path allows stored cross-site scripting (XSS) when other users view the topic action or activity log.

Affected products

Discourse Discourse Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0

Timeline

2026-09-24: disclosed
2026-08-25: patched: Fix committed; patches released in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0

References

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