Wekan: Shell Injection via Avatar Upload

published 2026-07-15 3 mo ago modified 2026-07-17 3 mo ago also EUVD-2026-44829

cvss: 9.9; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.8%; EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits: 0; none known

Wekan is open source kanban built with Meteor. Prior to 9.07, Wekan avatar upload functionality embeds user-supplied filenames into paths later passed to child_process.exec() for MIME-type detection. Because models/avatars.js and models/fileValidation.js used a shell command with the avatar filename, shell metacharacters such as backticks and $() in the filename could execute commands on the server. This issue is fixed in version 9.07.

Patch / fix

links 2

github.com/wekan/wekan@a4c74a5 commit
github.com/wekan/wekan/releases/tag/v9.07 release

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 3 mo ago (2026-07-17)

Exploit prediction

0.78% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.9	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected products

wekan wekan

Classification

Weakness

CWE-78 Improper Neutralization of Special Elements used in an OS Command
CWE-88 Improper Neutralization of Argument Delimiters in a Command

References

Sources

CVE List CVE-2026-52891
NVD CVE-2026-52891

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