Security readout for executives and security teams
Plain-English summary
CVE-2021-20770 is an authenticated cross-site scripting issue in Cybozu Garoon Message. If an attacker already has valid access, they may be able to inject script that runs in another user's browser. The public bundle does not provide CVSS, exploitation evidence, or a confirmed fix version.
Executive priority
Treat this as a targeted product exposure item, not a confirmed emergency. If the organization uses affected Garoon versions, assign ownership to validate vendor guidance and remediate. If Garoon is not present, no action is indicated from this CVE.
Technical view
The CVE describes XSS in Message of Cybozu Garoon versions 4.6.0 through 5.0.2. The vector is unspecified, and the attacker must be remote and authenticated. No CWE, CVSS score, proof of active exploitation, or patch details are included in the provided bundle.
Likely exposure
Exposure is limited to organizations running Cybozu Garoon 4.6.0 to 5.0.2, specifically the Message feature. Internet-facing or broadly accessible Garoon deployments may carry more practical risk, but the source bundle does not confirm deployment conditions.
Exploitation context
The sources support authenticated remote XSS only. There is no CISA KEV listing in the bundle, and no cited source here states active exploitation. The injection vector is not specified, so validation should avoid assumptions about a particular input field.
Researcher notes
Key unknowns are the specific XSS vector, exploit prerequisites beyond authentication, severity score, and fixed release details. Do not assume unauthenticated exploitation or active exploitation from the provided evidence. Use vendor and JVN references to refine remediation once advisory details are reviewed.
Mitigation direction
- Inventory Cybozu Garoon deployments and confirm exact versions.
- Prioritize Garoon 4.6.0 through 5.0.2 for vendor guidance review.
- Check Cybozu and JVN advisories for supported fixes or mitigations.
- Limit Garoon access to trusted users and networks where practical.
- Review account hygiene because exploitation requires authentication.
Validation and detection
- Confirm whether Cybozu Garoon is deployed in the environment.
- Record installed Garoon versions and compare against 4.6.0 through 5.0.2.
- Confirm whether the Message feature is enabled or used.
- Review vendor advisories for affected configuration details.
- Check security monitoring for suspicious authenticated Message activity.
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-2021-20770 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.