CVE-2026-91119
Discourse: Encode action_code_who in mention URLs
Description
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.
INFO
Published Date :
Sept. 24, 2026, 6:19 p.m.
Last Modified :
Sept. 24, 2026, 6:19 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-91119
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Upgrade Discourse to version 2026.1.8 or later.
- Upgrade Discourse to version 2026.6.3 or later.
- Upgrade Discourse to version 2026.7.2 or later.
- Upgrade Discourse to version 2026.8.0 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-91119.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-91119 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-91119
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-91119 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-91119 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Sep. 24, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N Added CWE CWE-79 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/91xxx/CVE-2026-91119.json">CVE-2026-91119</a> Added Reference https://github.com/discourse/discourse/commit/20dbf112760eb1d6a58f2e49aeef7546898b6f1c Added Reference https://github.com/discourse/discourse/commit/66653c484cfb91bc346f9a326f6945387f17b035 Added Reference https://github.com/discourse/discourse/commit/77a81c7a3a7ff9e94b355e32b8f379f2d389e05a Added Reference https://github.com/discourse/discourse/commit/c4748f651d9d2f3a6dd3106a4d5564536c645168 Added Reference https://github.com/discourse/discourse/pull/42882 Added Reference https://github.com/discourse/discourse/security/advisories/GHSA-pv3p-p3m9-v8v3