CVE-2026-27934 PUBLISHED

Discourse leaks private topic title and post excerpt via user action API endpoint

Assigner: GitHub_M
Reserved: 25.02.2026 Published: 19.03.2026 Updated: 19.03.2026

Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have a lack of visibility checks with a user action API endpoint that results in disclosure of the title and post excerpt to unauthorized users, leading to information disclosure. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	discourse
Product	discourse
Versions	Version >= 2026.1.0-latest, < 2026.1.2 is affected Version >= 2026.2.0-latest, < 2026.2.1 is affected Version = 2026.3.0-latest is affected

References

https://github.com/discourse/discourse/security/advisories/GHSA-824f-66wh-xx3g

Problem Types

CWE-201: Insertion of Sensitive Information Into Sent Data CWE