Vulnerability · Published Apr 14, 2026 · Assigned by GitHub_M

CVE-2026-34213Docmost has cross-page attachment overwrite via flawed attachmentId overwrite validation

Medium 5.4

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 14% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.

Severity (CVSS 3.1)5.4Medium

Exploit odds (30 days)0.2%top 85.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack tooling1Public PoC

Official description

Docmost is open-source collaborative wiki and documentation software. Starting in version 0.3.0 and prior to version 0.71.0, improper authorization in Docmost allows a low-privileged authenticated user to overwrite another page's attachment within the same workspace by supplying a victim `attachmentId` to `POST /api/files/upload`. This is a remote integrity issue requiring no victim interaction. Version 0.71.0 contains a patch.

Affected products (as reported)

Vendor	Product	Versions
docmost	docmost	>= 0.3.0, < 0.71.0

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

References

https://github.com/docmost/docmost/security/advisories/GHSA-89fp-2hch-j9gp x_refsource_CONFIRM