thumbler allows OS Command Injection

published 2026-03-25 7 mo ago modified 2026-06-17 4 mo ago also GHSA-mvhf-547c-h55r , EUVD-2026-15463

cvss: 9.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 2.4%; EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits: 0; none known

thumbler through 1.1.2 allows OS command injection via the input, output, time, or size parameter in the thumbnail() function because user input is concatenated into a shell command string passed to child_process.exec() without proper sanitization or escaping.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: total
Assessed: 7 mo ago (2026-03-28)

Exploit prediction

2.40% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/zebbernCVE/CVE-2026-26833 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
npm	thumbler	<=1.1.2	no fix listed

Classification

Weakness

CWE-94 Improper Control of Generation of Code
CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

github.com /zebbernCVE/CVE-2026-26833
web, exploit, vendor-advisory
github.com /mmahrous/thumbler
package, product
npmjs.com /package/thumbler
web, product
github.com /mmahrous/thumbler/blob/master/lib/thumbler.js
web, not-applicable
nvd.nist.gov /vuln/detail/CVE-2026-26833
advisory

Sources

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