Docmost: Unbounded ZIP decompression (zip-bomb) in page import allows denial of service

published 2026-09-24 45 d ago modified 2026-09-24 45 d ago also EUVD-2026-86386

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 22%
public exploits: 0; none known

Docmost is open-source collaborative wiki and documentation software. From 0.21.0 until 0.95.0, any authenticated workspace member with edit rights to a space can upload an archive to the page-import feature whose ZIP extraction routine does not limit total uncompressed size, per-entry size, or entry count. The extractor writes entries to the server temp directory and automatically extracts one nested ZIP, allowing an outer upload within the default 200 MB limit to expand by multiple GB. The resulting disk exhaustion can crash the import worker and degrade or take down the instance for all tenants. This issue is fixed in version 0.95.0.

Patch / fix

links 2

github.com/docmost/docmost@0411088 commit
github.com/docmost/docmost/releases/tag/v0.95.0 release

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 45 d ago (2026-09-24)

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

docmost docmost

Classification

Weakness

CWE-400 Uncontrolled Resource Consumption
CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)
CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

CVE List CVE-2026-65827
NVD CVE-2026-65827

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary