Security readout for executives and security teams
Plain-English summary
Craft CMS sites running versions before 3.6.7 had a potential remote code execution issue. The known trigger required an attacker to hijack an administrator session and the site to allow administrative changes, so this is serious but not described as unauthenticated or broadly exploitable.
Executive priority
Prioritize remediation for internet-facing Craft CMS sites and any environment where admin access is high value. The issue can become severe after administrator session compromise, but available sources do not show active exploitation.
Technical view
CVE-2021-27903 affects Craft CMS before 3.6.7. Public details describe potential RCE under limited circumstances: administrative changes were not restricted and an attacker somehow obtained an administrator session. The source bundle does not provide CVSS, CWE, detailed vulnerable components, or exploit mechanics.
Likely exposure
Exposure is most likely on Craft CMS installations below 3.6.7, especially production sites where administrative changes remain enabled and administrator sessions could be compromised.
Exploitation context
The provided sources do not report active exploitation, and CISA KEV status is false. Exploitation is described as conditional on hijacking an administrator session, so treat this as a post-compromise escalation risk rather than confirmed internet-wide exploitation.
Researcher notes
Evidence is sparse. The public description gives the key preconditions but not exploit path, CVSS, CWE, or affected component detail. Validate exposure through version checks and Craft CMS configuration review rather than exploit testing.
Mitigation direction
- Upgrade Craft CMS to 3.6.7 or later.
- Review Craft CMS security changelog and commit notes.
- Restrict administrative changes on production sites where supported.
- Harden administrator session security and monitor admin access.
- Check vendor guidance for any additional remediation.
Validation and detection
- Inventory Craft CMS versions across public and internal sites.
- Confirm affected systems are at least version 3.6.7.
- Verify production sites restrict administrative changes where appropriate.
- Review logs for unusual administrator sessions or configuration changes.
- Document any systems awaiting vendor-guided remediation.
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.
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.
Open ATT&CK lookupCVE-2021-27903 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/craftcms/cms/blob/develop/CHANGELOG.md#securityCVE reference · x_refsource_MISC
- https://github.com/craftcms/cms/commit/c17728fa0bec11d3b82c34defe0930ed409aec38CVE 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.