Answer in brief
CVE-2026-91123 records a High severity (CVSS 7.2) vulnerability in Discourse: Reject literal backslash path separators in iframe src traversal guard. The current sources do not mark it as known exploited. The current feed maps discourse/discourse (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps discourse/discourse (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| discourse/discoursegeneric | <2026.8.0 || >=2026.7.0-latest <2026.7.2 || >=2026.6.0-latest <2026.6.3 || >=2026.1.0-latest <2026.1.8 | 2026.8.0, 2026.7.2, 2026.6.3, 2026.1.8 |
Published upstream
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 25, 2026
Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, the iframe src traversal guard did not treat literal backslashes as path separators after decoded dot segments. A crafted source could therefore pass an allowed_iframes subpath check while browser URL normalization moved the iframe outside the intended allowed path. The resulting iframe could load content from a location that the administrator did not allow. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.
Quoted source text, attributed separately from HOL analysis.