Security readout for executives and security teams
Plain-English summary
Cybozu Garoon’s E-mail feature had an input-validation flaw that could let a logged-in remote user change email data they should not be allowed to modify. The issue affects Garoon 4.0.0 through 5.0.2. Treat this as a business integrity risk for organizations using Garoon email workflows.
Executive priority
Prioritize remediation if affected Garoon versions support regulated, executive, customer, or operational email workflows. If Garoon is not deployed or is outside the affected version range, urgency is lower but should still be documented.
Technical view
CVE-2021-20762 is an improper input validation vulnerability in Cybozu Garoon E-mail. The CVE states that a remote authenticated user can alter E-mail data without the appropriate privilege. The source bundle provides no CVSS score, CWE, proof of exploitation, or specific fixed version details beyond the affected range.
Likely exposure
Exposure is limited to Cybozu Garoon deployments running versions 4.0.0 through 5.0.2 with the E-mail feature in use. The attacker must be authenticated, based on the CVE description.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Risk comes from authenticated privilege bypass and unauthorized modification of email data, not from an unauthenticated internet-wide attack signal.
Researcher notes
Evidence is sparse in the provided bundle: no CVSS, CWE, exploit details, or patch version is included. The core issue is authenticated unauthorized data alteration in Garoon E-mail, so validation should focus on version exposure, feature use, permissions, and vendor advisory status.
Mitigation direction
- Inventory Cybozu Garoon versions and identify any 4.0.0 through 5.0.2 deployments.
- Review Cybozu and JVN advisories for vendor-approved update or workaround guidance.
- Restrict Garoon access to trusted users and networks where possible.
- Review email permission models for sensitive mailboxes and delegated access.
- Monitor Garoon audit logs for unexpected email data changes.
Validation and detection
- Confirm the installed Garoon version on each production and staging system.
- Verify whether the E-mail feature is enabled and business-critical.
- Check vendor advisories for the exact remediation status before closing risk.
- Review recent audit logs for unauthorized email data modification patterns.
- Confirm authenticated user roles cannot modify email data outside intended privileges.
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-2021-20762 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://cs.cybozu.co.jp/2021/007206.htmlCVE reference · x_refsource_MISC
- https://jvn.jp/en/jp/JVN54794245/index.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.