CVE-2026-91123Discourse: Reject literal backslash path separators in iframe src traversal guard
Updated under an hour ago ()
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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.
- CVSS
- 7.2 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- Weakness (CWE)
- CWE-22
- 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 24, 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-6pwj-wgg8-4rjcx-refsource-confirm
- https://github.com/discourse/discourse/pull/42882x-refsource-misc
- https://github.com/discourse/discourse/commit/042d7b159beda4f74d23e245e8b2e396d9ff8318x-refsource-misc
- https://github.com/discourse/discourse/commit/097ce5600a2d74d9c68e57974597ab2684bd2a24x-refsource-misc
- https://github.com/discourse/discourse/commit/0b5a27e689925edce9ba9b14110022435d2b94bex-refsource-misc
- https://github.com/discourse/discourse/commit/142f5155ad8e56ddb8012c4e70c69a03dedc0579x-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.