CVE-2026-34213: Docmost has cross-page attachment overwrite via flawed attachmentId overwrite validation
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 Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
docmostto a version that resolves this vulnerability.Fixed in 0.71.0
Event History
Frequently Asked Questions
What is the severity of CVE-2026-34213?
The severity of CVE-2026-34213 is considered to be medium due to the potential for unauthorized access and data manipulation.
How do I fix CVE-2026-34213?
To fix CVE-2026-34213, upgrade Docmost to version 0.71.0 or later.
Who is affected by CVE-2026-34213?
CVE-2026-34213 affects users of Docmost versions between 0.3.0 and 0.71.0.
What type of vulnerability is CVE-2026-34213?
CVE-2026-34213 is a cross-page attachment overwrite vulnerability caused by improper authorization.
Can low-privileged users exploit CVE-2026-34213?
Yes, low-privileged authenticated users can exploit CVE-2026-34213 to overwrite attachments.