Security readout for executives and security teams
Plain-English summary
CVE-2021-3040 is a code execution flaw in Bridgecrew Checkov by Prisma Cloud. A malicious Terraform file could trigger unsafe deserialization when processed by vulnerable Checkov 2.0 releases before 2.0.139. Checkov 1.0 is stated as not impacted.
Executive priority
Prioritize remediation where Checkov scans Terraform from multiple contributors or automated repositories. The rating is moderate, but successful exploitation could execute code in a security scanning context and affect confidentiality or integrity.
Technical view
The issue is CWE-502 unsafe deserialization during Terraform file processing. The source CVSS is 6.7, with high confidentiality and integrity impact, low availability impact, low attack complexity, and high privileges required. Affected scope is Checkov 2.0 before 2.0.139.
Likely exposure
Exposure is most likely where Checkov 2.0 before 2.0.139 processes Terraform files from repositories, contributors, or automation inputs. The bundle does not identify affected hosted services or other products.
Exploitation context
The source bundle does not show known active exploitation, and KEV status is false. Exploitation depends on getting a malicious Terraform file processed by vulnerable Checkov, with high privileges required according to the CVSS vector.
Researcher notes
Evidence is limited to the CVE record and Palo Alto Networks advisory metadata in the bundle. Do not infer active exploitation or broader product impact. The key exposure boundary is vulnerable Checkov 2.0 processing malicious Terraform input.
Mitigation direction
- Upgrade Checkov 2.0 deployments to version 2.0.139 or later.
- Confirm Checkov 1.0 deployments separately; sources state 1.0 is not impacted.
- Review Palo Alto Networks guidance for any updated vendor recommendations.
- Restrict who can introduce Terraform files into Checkov scanning workflows.
Validation and detection
- Inventory Checkov versions across developer workstations, CI, and automation systems.
- Identify any Checkov 2.0 installations earlier than 2.0.139.
- Review pipelines or jobs that scan Terraform files from shared repositories.
- Check vendor advisory status before closing remediation tickets.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-502: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution 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.
Open ATT&CK lookupCVE-2021-3040 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.7 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L
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.
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L1.25.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.7MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://security.paloaltonetworks.com/CVE-2021-3040CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Deserialization of Untrusted Data
Deserialization of Untrusted Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.