CVE-2026-26833: thumbler through 1.1.2 allows OS command injection via the input, output, time, or size parameter in the thumb

Q: How do I fix CVE-2026-26833?

thumbler: upgrade to newer than 1.1.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-26833 being exploited?

CVE-2026-26833 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-26833 affect?

CVE-2026-26833 affects thumbler. Severity is critical (CVSS 9.8). 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 sanit

Q: How urgent is CVE-2026-26833?

Priority 68/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-26833 is a critical-severity flaw (CVSS 9.8) affecting thumbler. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Critical severity
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.4% (top 16%)
CISA exploited list	No
Weakness	CWE-78, CWE-94
Published	2026-03-25
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: mmahrous

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-25 16:16 UTCPublished CVE record published
2026-06-17 10:26 UTCUpdated Record last modified

mmahrous thumbler UPGRADE

Affected: <= 1.1.2

Fixed in: newer than 1.1.2

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls thumbler

2. UPGRADE to newer than 1.1.2

npm install thumbler@">1.1.2"

Exact fixes by distribution

npm · thumbler · NO FIX YET · vulnerable: <= 1.1.2 · source

Fedora ELN · perl-Encode · FIXED · 3.25-528.eln159 · FEDORA-2026-79991d0238 · source

sudo dnf upgrade --advisory=FEDORA-2026-79991d0238

Fedora 46 · fonttools · FIXED · 4.68.0-1.fc46 · FEDORA-2026-65d6c01c75 · source

sudo dnf upgrade --advisory=FEDORA-2026-65d6c01c75

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: zebbernCVE/CVE-2026-26833 (0 stars)

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-26833?

thumbler: upgrade to newer than 1.1.2. Exact commands for each OS are on this page.

Is CVE-2026-26833 being exploited?

CVE-2026-26833 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-26833 affect?

CVE-2026-26833 affects thumbler. Severity is critical (CVSS 9.8). 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 sanit

How urgent is CVE-2026-26833?

Priority 68/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

References

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