Is CVE-2026-27021 in the CISA KEV catalog?

No. CVE-2026-27021 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-27021?

CVE-2026-27021 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-27021?

CVE-2026-27021 has an EPSS score of 0.28% (20th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-27021?

Upgrade discourse to 2026.1.1 or later.

CVE & CISA-KEV Catalog

CVE-2026-27021

MEDIUM

5.3

CVSS v3

NVD

Description

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, the voters endpoint in the poll plugin lacked post visibility checks which allowed unauthorized access to voters details of polls in any post. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.

CWE-862Missing Authorization

How to fix

Remediation Available

discourseNVD

Affected:>= 2026.1.0, < 2026.1.1Fixed in:2026.1.1CVE-2026-27021derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Exploit Intelligence

0.28%probability of exploitation in 30 days

20thpercentile

Low risk: more likely to be exploited than 20% of all known CVEs.

References

Vendor Advisory1

github.com

Related Vulnerabilities

Other CWE-862 (Missing Authorization) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2021-39226	Critical	9.8	100%	KEV	Fix
CVE-2022-0543	Critical	10.0	100%	KEV	Fix
CVE-2021-21978	Critical	9.8	99%	-	Fix
CVE-2023-52163	High	8.8	96%	KEV	-
CVE-2022-1329	High	8.8	93%	-	-
CVE-2023-6875	Critical	9.8	90%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-02.