Discourse: Encode action_code_who in mention URLs
Historical advisory recorded 23 Oct 2026 15:48:27 UTC. Read the latest advisory.
cve-program · CVE-2026-91119
PublishedDiscourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the topic small-action and nested-activity-log components interpolated the free-form action_code_who value into mention-link href attributes without URL encoding. A quote-bearing display name could terminate the intended URL attribute and inject attacker-controlled elements into the trusted rendered markup. Although the visible mention text was escaped, the unencoded path component allowed stored HTML injection when another user viewed the affected topic action or activity log. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.
Read the publisher's advisoryAffected versions, risk and source history
Related advisories and sources
Publishers link these advisories through the identifiers shown below. A shared identifier or date alone does not tell you whether your software is affected or whether the advisories describe the same cause.
CVE-2026-91119 · CVE overview and exploitation status
cve-program · CVE-2026-91119
- https://github.com/discourse/discourse/security/advisories/GHSA-pv3p-p3m9-v8v3
- https://github.com/discourse/discourse/pull/42882
- https://github.com/discourse/discourse/commit/20dbf112760eb1d6a58f2e49aeef7546898b6f1c
- https://github.com/discourse/discourse/commit/66653c484cfb91bc346f9a326f6945387f17b035
- https://github.com/discourse/discourse/commit/77a81c7a3a7ff9e94b355e32b8f379f2d389e05a
- https://github.com/discourse/discourse/commit/c4748f651d9d2f3a6dd3106a4d5564536c645168
This historical advisory does not include today's related changes. Open the latest advisory to find current connections.