Discourse: Shared-draft titles and excerpts leak through group post serialization

published 2026-08-17 2 mo ago modified 2026-10-05 34 d ago also BIT-discourse-2026-55704 , EUVD-2026-60237 , GHSA-fxw4-38v9-76v8

cvss: 4.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits: 0; none known

Discourse is an open-source discussion platform. Prior o 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, users who were allowed to view a group’s activity, but were not permitted to see shared drafts, could still receive shared-draft entries through the group posts and group mentions endpoints. This could disclose shared-draft topic titles and post excerpt/content, resulting in an information disclosure of unpublished draft material. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.

Patch / fix

fixed in 2

bitnami discourse 2026.1.6, 2026.5.2, 2026.6.1
discourse discourse 2026.1.6, 2026.5.2, 2026.6.1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 mo ago (2026-08-17)

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
OSV	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
bitnami	discourse	<2026.1.6 >=2026.5.0, <2026.5.2 >=2026.6.0, <2026.6.1	2026.1.6 2026.5.2 2026.6.1

Affected products

discourse discourse

Classification

Weakness

CWE-862 Missing Authorization

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary