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TI-2026-26508 Aliases CVE-2026-34213

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

Priority LOW 24CWE-639Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · Low · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-639.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00233 14th percentileScored 2026-11-07
Fix Fixed docmost (docmost): 0.71.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
docmostdocmost0.3.0 to before 0.71.00.71.0Patch availableCNA
  • docmost Vendordocmost Affected 0.3.0 to before 0.71.0 Fixed in 0.71.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:docmost:docmost:*:*:*:*:*:*:*:*0.3.0 to before 0.71.0Vulnerabledocmost
  • cpe:2.3:a:docmost:docmost:*:*:*:*:*:*:*:* Versions 0.3.0 to before 0.71.0 Vulnerable ·docmost

Remediation

  • Fix · CNA docmost (docmost) Fixed in 0.71.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-34213

References

Advisory 1

  • TI-2026-17859 Docmost affected by an Arbitrary File Write via Zip Import Feature (ZipSlip) CVSS 3.1CRITICAL 9.8
  • TI-2026-19373 Docmost Affected by Stored XSS in Public Share Page CVSS 3.1HIGH 7.3
  • TI-2025-35043 Cross Site Scripting vulnerability in docmost v.0.21.0 and before allows an attacker to execute arbitrary code CVSS 3.1MEDIUM 6.1
  • TI-2026-19029 Docmost is vulnerable to stored Cross-Site Scripting (XSS) through Mermaid rendering CVSS 4.0MEDIUM 6.3
  • TI-2026-26507 Docmost page content has stored XSS via unsanitized attachment URLs CVSS 3.1MEDIUM 5.4
  • TI-2026-29581 Docmost: XSS in Comments with JavaScript URI CVSS 3.1MEDIUM 5.4
See all 8 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences