CVE-2026-91119Discourse: Encode action_code_who in mention URLs
Updated under an hour ago ()
Does this affect you?
It affects discourse. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
Discourse 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.
- CVSS
- 6.4 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- Weakness (CWE)
- CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Sep 28, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
discourse discourse discourse:discourse (from the name) | before 2026.8.0; from 2026.7.0-latest, < 2026.7.2; from 2026.6.0-latest, < 2026.6.3; from 2026.1.0-latest, < 2026.1.8 | CNA record |
References
- https://github.com/discourse/discourse/security/advisories/GHSA-pv3p-p3m9-v8v3x-refsource-confirm
- https://github.com/discourse/discourse/pull/42882x-refsource-misc
- https://github.com/discourse/discourse/commit/20dbf112760eb1d6a58f2e49aeef7546898b6f1cx-refsource-misc
- https://github.com/discourse/discourse/commit/66653c484cfb91bc346f9a326f6945387f17b035x-refsource-misc
- https://github.com/discourse/discourse/commit/77a81c7a3a7ff9e94b355e32b8f379f2d389e05ax-refsource-misc
- https://github.com/discourse/discourse/commit/c4748f651d9d2f3a6dd3106a4d5564536c645168x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.