CVE-2026-91123
7.2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
Summary
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| discourse | discourse | < 2026.8.0 | affected |
| discourse | discourse | >= 2026.7.0-latest, < 2026.7.2 | affected |
| discourse | discourse | >= 2026.6.0-latest, < 2026.6.3 | affected |
| discourse | discourse | >= 2026.1.0-latest, < 2026.1.8 | affected |
Weaknesses
- CWE-22: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
ADP Enrichment
CISA ADP Vulnrichment
- SSVC:
- Exploitation: none
- Automatable: yes
- Technical Impact: partial
References
- https://github.com/discourse/discourse/security/advisories/GHSA-6pwj-wgg8-4rjc
- https://github.com/discourse/discourse/pull/42882
- https://github.com/discourse/discourse/commit/042d7b159beda4f74d23e245e8b2e396d9ff8318
- https://github.com/discourse/discourse/commit/097ce5600a2d74d9c68e57974597ab2684bd2a24
- https://github.com/discourse/discourse/commit/0b5a27e689925edce9ba9b14110022435d2b94be
- https://github.com/discourse/discourse/commit/142f5155ad8e56ddb8012c4e70c69a03dedc0579
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