Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a type coercion issue in a post actions API endpoint allowed non-staff users to issue warnings to other users. Warnings are a staff-only moderation feature. The vulnerability required the attacker to be a logged-in user and to send a specifically crafted request. No data exposure or privilege escalation beyond the ability to create unauthorized user warnings was possible. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.
CVE-2026-27491
MEDIUMNVD 4.34.3Trending — 3 sources updated this week
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 4.3 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: nvd
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 4.3
- EG Score
- 4.3(low)
- EG Risk
- 24(Track)EG Risk 24/100SSVC: Track
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 computedSeverity43% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 25%
- KEV
- Not listed
Published
March 19, 2026
Last Modified
June 17, 2026
References (4)
- security-advisories@githubhttps://github.com/discourse/discourse/commit/60a588f4da4ab0feceb2c44787d4261b4f8757be
- security-advisories@githubhttps://github.com/discourse/discourse/commit/d3cb203feabc46d765ecb91f348613a2bd531b89
- security-advisories@githubhttps://github.com/discourse/discourse/commit/f5fef73827da7520efc517357bd2a6bab35d7886
- security-advisories@githubhttps://github.com/discourse/discourse/security/advisories/GHSA-xq37-5fvf-4m4j
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 5× in last 7d / 5× 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.
- 2026-07-30 16:27 UTCEPSS rescore
- 2026-07-30 01:30 UTCEPSS rescore
- 2026-07-28 15:36 UTCEPSS rescore
- 2026-07-27 14:38 UTCEG score recompute
- 2026-07-27 14:27 UTCOSV refresh
Related CVEs(same CWE)
Same CWE
10 shownCWE-862
- CVE-2013-3960EG 9.9CRITICAL
- CVE-2015-10143EG 9.8CRITICAL
- CVE-2016-11036EG 9.8CRITICAL
- CVE-2018-11541EG 9.8CRITICAL
- CVE-2011-4183NVD 6.5EG 9.8CRITICAL
- CVE-2018-10251EG 9.8EPSS p91CRITICAL
- CVE-2018-1217EG 9.8EPSS p99CRITICAL
- CVE-2018-0015EG 9.8CRITICAL
- CVE-2017-12582EG 9.8CRITICAL
- CVE-2017-1000056EG 9.8CRITICAL
Frequently asked(5)
What is CVE-2026-27491?
CVE-2026-27491 is a medium vulnerability published on March 19, 2026. Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, a type coercion issue in a post actions API endpoint allowed non-staff users to issue warnings to other users. Warnings are a staff-only moderation feature. The vulnerability required the…
When was CVE-2026-27491 disclosed?
CVE-2026-27491 was first published in the National Vulnerability Database on March 19, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-27491 actively exploited?
CVE-2026-27491 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 74.9% of all scored CVEs.
What is the CVSS score of CVE-2026-27491?
CVE-2026-27491 has a CVSS v3 base score of 4.3 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-27491?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-27491, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-27491
Is Your Infrastructure Affected by CVE-2026-27491?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.