Security readout for executives and security teams
Plain-English summary
This issue exposed Grammarly Chrome extension authentication tokens to websites that should not have been able to access them. A malicious site could potentially learn a user token and affect that user’s Grammarly account/session. The supplied data says versions before February 2, 2018 were affected.
Executive priority
Prioritize cleanup if your organization allowed Grammarly in Chrome during 2018 or retains old unmanaged browser profiles. For modern managed browsers with current extensions, urgency is lower but still worth confirming through extension inventory.
Technical view
CVE-2018-6654 affects the Grammarly extension for Chrome before 2018-02-02. The flaw was improper restriction of token exposure: an extension iframe could return user authentication token data without binding that access to a specific trusted website. No CVSS, CWE, or vendor advisory details are included in the bundle.
Likely exposure
Exposure is likely limited to users who had the Grammarly Chrome extension installed before the February 2, 2018 fix date. Current exposure depends on whether old browser profiles, unmanaged endpoints, or archived extension versions remain in use.
Exploitation context
The source bundle does not show active exploitation, and the CVE is not marked KEV. The issue was publicly documented through a Project Zero reference, so defenders should treat it as known public vulnerability history, not confirmed ongoing exploitation.
Researcher notes
The public bundle is sparse: no CVSS vector, CWE, patch note, or affected version identifier beyond the date cutoff. Analysis should stay anchored to the CVE description and Project Zero reference. Avoid assuming impact beyond token disclosure for the Grammarly Chrome extension.
Mitigation direction
- Update or remove any Grammarly Chrome extension version older than 2018-02-02.
- Use browser management to block outdated extension versions where possible.
- Check vendor or Chrome Web Store guidance for current supported versions.
- Limit unmanaged browser extensions on corporate endpoints.
Validation and detection
- Inventory Chrome extensions across managed endpoints and browser profiles.
- Identify any Grammarly extension installations predating 2018-02-02.
- Review endpoint telemetry for unmanaged or sideloaded extension copies.
- Confirm extension update enforcement in browser management policy.
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-2018-6654 mapping review
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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://bugs.chromium.org/p/project-zero/issues/detail?id=1527CVE 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.