CVE-2026-34213

Docmost has cross-page attachment overwrite via flawed attachmentId overwrite validation

MEDIUM
5.4
CVSS Score
Published: April 14, 2026 at 09:49 PM UTC
Updated: July 24, 2026 at 10:20 PM UTC
1 product affected across 1 vendorDocmost

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.71.00.3.0 ≤ v < 0.71.0
Affected range stops below 0.71.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_CONFIRMVendor Advisory
Source: cverecord
https://github.com/docmost/docmost/security/advisories/GHSA-89fp-2hch-j9gp

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.4MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-639

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