Security readout for executives and security teams
Plain-English summary
MockServer can let a malicious website compromise a machine running it locally. The issue combines permissive CORS with scriptable dynamic expectations, allowing code to run as MockServer after a developer visits an attacker-controlled page.
Executive priority
Treat this as a developer-environment compromise risk. It is not listed as actively exploited, but arbitrary code execution on engineering machines can expose credentials, source code, and internal access.
Technical view
MockServer’s broad default CORS policy permits cross-site requests from arbitrary origins. Its JavaScript and Velocity dynamic expectation features can execute code in the MockServer context. The attack requires user interaction and a reachable MockServer instance.
Likely exposure
Most likely exposure is developer workstations, test environments, or CI systems running MockServer. The source bundle lists mock-server MockServer as affected across all versions, but does not name a fixed version.
Exploitation context
The bundle does not show CISA KEV listing or confirmed active exploitation. It references a GitHub Security Lab advisory with proof-of-concept details, so public technical knowledge exists.
Researcher notes
The core risk is issue chaining: cross-origin request acceptance plus script injection through dynamic expectations. Evidence in the bundle is sufficient for exposure assessment, but incomplete on patched versions or vendor-endorsed mitigations.
Mitigation direction
- Check MockServer vendor guidance for fixed versions or recommended configuration changes.
- Restrict MockServer CORS origins to trusted development hosts only.
- Disable or tightly control JavaScript and Velocity dynamic expectations where possible.
- Avoid browsing untrusted sites from systems running MockServer.
- Do not expose MockServer beyond trusted local or test networks.
Validation and detection
- Inventory developer, CI, and test systems running MockServer.
- Review MockServer configuration for permissive CORS settings.
- Identify usage of JavaScript or Velocity dynamic expectations.
- Confirm whether MockServer is reachable from browsers on developer machines.
- Check vendor advisories for current remediation status.
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-74: Exact CWE lookup
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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-2021-32827 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
- 6.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N
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:H/PR:N/UI:R/S:C/C:N/I:H/A:N1.64Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://securitylab.github.com/advisories/GHSL-2021-059-mockserver/CVE reference · x_refsource_CONFIRM
- https://www.oracle.com/security-alerts/cpujan2022.htmlCVE 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.
Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.