Vulnerability · Published Sep 24, 2026 · Assigned by GitHub_M

CVE-2026-52850Docmost: Broken access control in transclusion lookup API leaks sync-block content across private spaces

Medium 4.3

In plain English

A medium-severity authorization bypass via user-controlled key in docmost from docmost. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities).

Severity (CVSS 3.1)4.3Medium

Exploit odds (30 days)0.2%top 91.0% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Docmost is open-source collaborative wiki and documentation software. Prior to 0.90.1, an authenticated workspace member who does not belong to a private space can call the transclusion / sync-block lookup API with a known sourcePageId and transclusionId pair because the lookup does not enforce private space membership before resolving the source page. The API can return confidential sync-block content and source page metadata even though the normal page APIs deny access to the same page. This issue is fixed in version 0.90.1.

Affected products (as reported)

Vendor	Product	Versions
docmost	docmost	< 0.90.1

Weakness: CWE-639, CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

References

https://github.com/docmost/docmost/security/advisories/GHSA-5vhf-cgf2-c9cq x_refsource_CONFIRM
https://github.com/docmost/docmost/commit/830b5b4d458a1302f42c8b68bff9ff559f6eb342 x_refsource_MISC
https://github.com/docmost/docmost/releases/tag/v0.90.1 x_refsource_MISC