Security readout for executives and security teams
Plain-English summary
Concrete CMS versions through 8.5.5 had a path traversal issue that could let an attacker read files the application can access and trigger server-side requests. That creates risk of sensitive file disclosure and internal network probing from the web server.
Executive priority
Treat this as a high-priority exposure for public Concrete CMS sites because it may disclose sensitive files and enable SSRF. Prioritize confirming versions, upgrading affected systems, and reviewing logs where sensitive data or internal services are reachable.
Technical view
CVE-2021-40103 is described as path traversal in Concrete CMS through 8.5.5, leading to arbitrary file read and SSRF. The bundle does not include CVSS, CWE, vulnerable endpoint details, or exploit preconditions, so severity must be assessed from deployed exposure and data sensitivity.
Likely exposure
Exposure is most likely on Concrete CMS deployments running 8.5.5 or earlier, especially public websites. The source bundle does not identify affected CPEs or components beyond Concrete CMS through 8.5.5.
Exploitation context
The source bundle does not state active exploitation, and KEV is false. A HackerOne report is cited, but the prompt bundle does not provide enough detail to confirm exploit maturity or public weaponization.
Researcher notes
Evidence is limited to the CVE description, HackerOne reference, and Concrete CMS 8.5.6 release notes reference. The bundle lacks endpoint, authentication, CVSS, and CWE detail, so validation should focus on asset versioning and vendor-noted remediation rather than exploit reproduction.
Mitigation direction
- Inventory Concrete CMS versions and identify installs at 8.5.5 or earlier.
- Review Concrete CMS 8.5.6 release notes and vendor upgrade guidance.
- Upgrade affected Concrete CMS deployments according to vendor instructions.
- Restrict unnecessary server egress to reduce SSRF impact.
- Review access controls around sensitive local files.
Validation and detection
- Confirm each Concrete CMS instance version from administrative or deployment records.
- Check whether public-facing instances are 8.5.5 or earlier.
- Review web and application logs for unusual file access patterns.
- Review outbound server request logs for unexpected internal destinations.
- Verify upgraded systems are no longer on affected versions.
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.
Cloud metadata behavior lookup
The CVE wording references SSRF or metadata access, so cloud discovery and credential material review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-40103 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://hackerone.com/reports/1102211CVE reference · x_refsource_MISC
- https://documentation.concretecms.org/developers/introduction/version-history/856-release-notesCVE 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.