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CVE Record

CVE-2026-29514: NetBox 4.3.5 - 4.5.4 RCE via RenderTemplateMixin

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 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.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

Authenticated NetBox users with template-related permissions may be able to run code on the NetBox server. This can compromise data confidentiality, integrity, and availability because execution occurs as the NetBox service user. The provided sources do not show confirmed active exploitation.

Executive priority

Prioritize remediation for production or externally reachable NetBox deployments. This is a high-impact authenticated RCE affecting infrastructure source-of-truth systems, so compromise could expose network inventory and enable operational disruption.

Technical view

NetBox 4.3.5 through 4.5.4 expose RCE in RenderTemplateMixin.get_environment_params(). Users with exporttemplate or configtemplate permissions can set environment_params, including finalize, to importable Python callables. Jinja2 sandbox protections are bypassed because finalize runs during expression rendering outside sandbox call interception.

Likely exposure

Exposure is likely where NetBox versions 4.3.5 through 4.5.4 are deployed and authenticated users can create or modify export/config templates. Internet-facing NetBox increases urgency, but the described issue requires valid credentials and specific permissions.

Exploitation context

The bundle includes a public technical writeup tagged exploit and a VulnCheck advisory. KEV is false, and no supplied source confirms active exploitation in the wild. Treat exploitability as practical but not confirmed as actively exploited.

Researcher notes

Focus validation on permissioned template workflows and the RenderTemplateMixin environment parameter path. The key security boundary issue is user-controlled callables in Jinja2 environment configuration, especially finalize, which executes outside normal sandbox call checks.

Mitigation direction

  • Inventory NetBox versions and identify systems running 4.3.5 through 4.5.4.
  • Apply the vendor release or branch containing the cited patch commit.
  • Review NetBox v4.6.1 release notes and upstream fixed-branch guidance.
  • Restrict exporttemplate and configtemplate permissions to trusted administrators only.
  • Review recent template changes by users with those permissions.

Validation and detection

  • Confirm deployed NetBox version is outside the affected range or includes the cited patch.
  • List users and groups with exporttemplate or configtemplate permissions.
  • Audit export and config templates for environment_params usage.
  • Review NetBox service logs for suspicious template rendering activity.
  • Validate remediation in staging before production rollout.
Prepared
Confidence
high
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-183: Exact CWE lookup

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description · low confidence lookup

Execution behavior lookup

The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2026-29514 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
3Timeline events
1ADP providers
8Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.8CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9VulnCheck
8.7CVSS 4.0HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——VulnCheck

Vulnerability scoring details

Base CVSS 4.0 score

8.7High
CVSS 4.0 vector shape for CVE-2026-29514Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
netbox-communitynetbox4.3.5affected
Weakness

CWE details

CWE-183

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-183 · source CWE mapping

Permissive List of Allowed Inputs

Permissive List of Allowed Inputs represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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