Security readout for executives and security teams
Plain-English summary
ExpressionEngine before 6.0.3 used a user-supplied file parameter when serving add-on icons. The cited record does not state the full impact, but trusting a request value for file selection is unsafe and should be treated as an exposure risk for older installations.
Executive priority
Prioritize routine remediation for older ExpressionEngine sites, especially public-facing systems. Urgency is constrained by missing severity and exploitation evidence, but the trust-boundary flaw justifies prompt upgrade planning.
Technical view
The issue is in Addons/file/mod.file.php, where addonIcon relied on input->get('file') instead of fixed icon file names, icon.png and icon.svg. Public data lacks CVSS, CWE, exploitability, and impact detail.
Likely exposure
Exposure is limited to ExpressionEngine installations running versions before 6.0.3. The provided sources do not identify affected configurations, authentication requirements, or whether hosted deployments are exposed.
Exploitation context
CISA KEV status is false in the source bundle, and no cited source reports active exploitation. The available evidence only supports unsafe file-name input handling, not confirmed exploitation in the wild.
Researcher notes
The public record is sparse: no CVSS, CWE, exploit status, or precise impact is provided. Analysis should stay focused on the changed addonIcon file-selection behavior and avoid assuming arbitrary file read or remote code execution without additional evidence.
Mitigation direction
- Upgrade ExpressionEngine installations before 6.0.3 to version 6.0.3 or later.
- Review ExpressionEngine 6.0.3 release notes and vendor guidance.
- Inventory internet-facing ExpressionEngine sites and confirm their exact version.
- Prioritize unsupported or externally reachable installations for remediation.
Validation and detection
- Check whether any deployed ExpressionEngine instance is earlier than 6.0.3.
- Confirm addonIcon uses fixed icon.png and icon.svg names after update.
- Review application logs for unusual requests involving add-on icon file parameters.
- Document whether the affected code path is reachable in your deployment.
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.
CVE-2021-33199 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/ExpressionEngine/ExpressionEngine/releases/tag/6.0.3CVE reference · x_refsource_MISC
- https://github.com/ExpressionEngine/ExpressionEngine/compare/6.0.1...6.0.3#diff-17bcb23e5666fc2dccb79c7133e9eeb701847f67ae84fbde0a673c3fd3d109e0R508CVE 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.