Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-26833 is a critical-severity OS Command Injection (CWE-78) vulnerability in Mmahrous Thumbler. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 18% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-26833 is an OS command injection vulnerability affecting the thumbler npm package through version 1.1.2. The flaw occurs in the thumbnail() function within lib/thumbler.js, where user-supplied values for the input, output, time, or size parameters are concatenated directly into a shell command string passed to child_process.exec() without sanitization or escaping. This issue corresponds to CWE-78 (Improper Neutralization of Special Elements used in an OS Command) and CWE-94 (Improper Control of Generation of Code), earning a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
A remote, unauthenticated attacker can exploit this vulnerability over the network with low complexity and no user interaction required. By supplying malicious payloads in the affected parameters, the attacker can inject arbitrary OS commands, leading to remote code execution on the host system. Exploitation could result in high-impact compromise, including unauthorized data access, modification, or disruption of the affected application.
Mitigation details and patches can be found in the referenced advisories, including the thumbler GitHub repository (https://github.com/mmahrous/thumbler), source code (https://github.com/mmahrous/thumbler/blob/master/lib/thumbler.js), dedicated CVE repository (https://github.com/zebbernCVE/CVE-2026-26833), and npm package page (https://www.npmjs.com/package/thumbler). The vulnerability was published on 2026-03-25.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-15463
Vulnerability Data
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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.2.5V1.2.8V15.2.5V1.3.1
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover missing or incorrect command sanitization during development.
Input validation directly neutralizes or rejects special characters that would otherwise alter OS command structure.
Least privilege reduces the permissions available to any process that could be subverted by injected commands.
Least functionality restricts available OS commands and interpreters, limiting the blast radius of injection.
Requiring documented secure development standards and tools enforces use of safe code-generation APIs and escaping.
Secure engineering principles require proper neutralization of untrusted input before command construction.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.
Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).
PR.DS-10 protects runtime data confidentiality/integrity but has no bearing on neutralizing externally influenced input during code generation, so neither direction shows any preventive effect.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing and code review target insecure use of operating-system command interfaces, catching command-injection flaws introduced during development.
Banning unapproved code samples and unauthenticated web services, combined with secure-coding standards and SAST, prevents the dynamic generation or inclusion of attacker-supplied code.
Controls that restrict unauthorized or malicious code from being introduced via external networks or removable media limit opportunities for an attacker to inject and execute arbitrary code.