CVE-2026-91132

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1% (2nd percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 4.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowed_iframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched the allowed domain text, while browser URL parsing selected a different attacker-controlled origin. A user with posting privileges could exploit the flaw through a post or a Onebox oEmbed response and cause an attacker-controlled iframe to be rendered independently of the allowlisted domain. Successful exploitation requires a site-configured wildcard iframe pattern and the ability to create a post or trigger an oEmbed request for an attacker-controlled URL. This issue is fixed in versions 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0.

CVSS v3
4.3
EG Score
4.3MEDIUMmedium confidence
EG Risk
19
EG Risk 19/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity43% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.1%
EPSS %ILE
2nd
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 24, 2026

Last Modified

September 29, 2026

Advisory Details (6)

Auto-updated Sep 24, 2026
Patch available. Sources: github, github_pr, github_commit.
github_commit

commit db8064f2a2a2 (discourse/discourse)

Fix landed in discourse/discourse commit db8064f2a2a2 — awaiting tagged release

https://github.com/discourse/discourse/commit/db8064f2a2a2a3feb3308a1c932ac61d950c9e56
github_commit

commit d88e02ceb2ee (discourse/discourse)

Fix landed in discourse/discourse commit d88e02ceb2ee — awaiting tagged release

https://github.com/discourse/discourse/commit/d88e02ceb2eede4d8b851d9fe8aef753f3aa40b9
github_commit

commit d5ae0940707f (discourse/discourse)

Fix landed in discourse/discourse commit d5ae0940707f — awaiting tagged release

https://github.com/discourse/discourse/commit/d5ae0940707f95da5bc4562f7b544243e3103f8a
github_commit

commit 80968704c1ac (discourse/discourse)

Fix landed in discourse/discourse commit 80968704c1ac — awaiting tagged release

https://github.com/discourse/discourse/commit/80968704c1acb1d2ea2c6011dbf6c02ff13238e5
github_pr

Security fixes for main

Fix merged in discourse/discourse PR #42882 on 2026-08-25 — awaiting tagged release

https://github.com/discourse/discourse/pull/42882
github Patch Available

Wildcard iframe origin allowlist bypass via authority separators · Advisory · discourse/discourse · GitHub

https://github.com/discourse/discourse/security/advisories/GHSA-4q3q-hph3-3rvp

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 20× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-05 04:56 UTCEG score recompute
  2. 2026-10-04 23:22 UTCEPSS rescore
  3. 2026-10-04 04:43 UTCEG score recompute
  4. 2026-10-03 04:30 UTCEG score recompute
  5. 2026-10-02 04:17 UTCEG score recompute
  6. 2026-10-01 19:51 UTCEPSS rescore
  7. 2026-10-01 03:56 UTCEG score recompute
  8. 2026-09-30 15:04 UTCEPSS rescore
  9. 2026-09-29 03:30 UTCEG score recompute
  10. 2026-09-29 03:02 UTCEG score recompute
  11. 2026-09-28 18:55 UTCEG score recompute
  12. 2026-09-28 13:52 UTCEPSS rescore
  13. 2026-09-28 13:52 UTCEPSS rescore
  14. 2026-09-27 18:42 UTCEG score recompute
  15. 2026-09-27 13:49 UTCEPSS rescore
  16. 2026-09-26 18:29 UTCEG score recompute
  17. 2026-09-26 15:59 UTCEPSS rescore
  18. 2026-09-24 17:33 UTCEG score recompute
  19. 2026-09-24 17:02 UTCEG score recompute
  20. 2026-09-24 17:01 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-91132?
CVE-2026-91132 is a medium vulnerability published on September 24, 2026. Discourse is an open-source discussion platform. Prior to 2026.1.8, 2026.6.3, 2026.7.2, and 2026.8.0, sites using wildcard patterns in the allowed_iframes setting could accept a crafted iframe URL whose allowlisted suffix appeared after a URL authority separator. The wildcard origin check matched…
When was CVE-2026-91132 disclosed?
CVE-2026-91132 was first published on September 24, 2026, with the most recent update on September 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-91132 actively exploited?
CVE-2026-91132 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (2nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-91132?
CVE-2026-91132 has a CVSS base score of 4.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-91132?
A fix for CVE-2026-91132 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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