How severe is CVE-2018-6654?

CVE-2018-6654 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-6654 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-6654?

CVE-2018-6654 affects Grammarly. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-6654?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-6654 published?

CVE-2018-6654 was published on 2018-02-06 and last updated on 2026-06-17.

CVE-2018-6654

CVE-2018-6654 is a high-severity vulnerability in Grammarly with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-346.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (40th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-346
Affected product: Grammarly
Published: 2018-02-06
Last modified: 2026-06-17

Description

The Grammarly extension before 2018-02-02 for Chrome allows remote attackers to discover authentication tokens via an 'action: "user"' request to iframe.gr_-ifr, because the exposure of these tokens is not restricted to any specific web site.

Frequently asked questions

What is CVE-2018-6654?: The Grammarly extension before 2018-02-02 for Chrome allows remote attackers to discover authentication tokens via an 'action: "user"' request to iframe.gr_-ifr, because the exposure of these tokens is not restricted to any specific web site.
How severe is CVE-2018-6654?: CVE-2018-6654 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-6654 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-6654?: CVE-2018-6654 affects Grammarly. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-6654?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-6654 published?: CVE-2018-6654 was published on 2018-02-06 and last updated on 2026-06-17.

References

https://bugs.chromium.org/p/project-zero/issues/detail?id=1527

Affected products (1)

cpe:2.3:a:grammarly:grammarly:2018-02-02:*:*:*:*:chrome:*:*

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