CVE-2026-29514
Published: 04 May 2026
Summary
CVE-2026-29514 is a high-severity Permissive List of Allowed Inputs (CWE-183) vulnerability. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 48.6% 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 are NIST 800-53 AC-6 (Least Privilege) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2026-29514 is a remote code execution vulnerability in NetBox versions 4.3.5 through 4.5.4. The flaw exists in the RenderTemplateMixin.get_environment_params() method, which allows authenticated users with exporttemplate or configtemplate permissions to inject malicious Python callables into the environment_params field. This bypasses Jinja2 SandboxedEnvironment protections by setting the finalize parameter to any importable Python callable, such as subprocess.getoutput, which is invoked on every rendered expression outside the sandbox's call interception mechanism.
An attacker with the requisite permissions can exploit this vulnerability remotely over the network with low complexity and no user interaction. Successful exploitation grants arbitrary code execution as the NetBox service user, providing high confidentiality, integrity, and availability impact. The vulnerability carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and is classified under CWE-183.
Advisories from VulnCheck and Chocapikk detail the issue, while the NetBox GitHub repository includes discussion in issue #22079 and a patch in pull request #22078, published on 2026-05-04.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-26997
Vulnerability details
NetBox versions 4.3.5 through 4.5.4 contain a remote code execution vulnerability in the RenderTemplateMixin.get_environment_params() method that allows authenticated users with exporttemplate or configtemplate permissions to execute arbitrary code by specifying malicious Python callables in the environment_params field. Attackers can bypass…
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Jinja2 SandboxedEnvironment protections by setting the finalize parameter to any importable Python callable such as subprocess.getoutput, which is invoked on every rendered expression outside the sandbox's call interception mechanism, achieving remote code execution as the NetBox service user.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
RCE in public-facing NetBox web app via authenticated SSTI bypass of Jinja2 sandbox directly maps to T1190 exploitation and T1059.006 Python command execution (subprocess.getoutput etc.).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Timely flaw remediation through patching NetBox directly eliminates the RCE vulnerability in the RenderTemplateMixin.get_environment_params() method.
Enforcing least privilege restricts exporttemplate and configtemplate permissions to only essential users, preventing unauthorized exploitation by authenticated attackers.
Information input validation on the environment_params field blocks injection of malicious Python callables, addressing the core bypass of Jinja2 sandbox protections.