CVE-2021-37518: Universal Cross Site Scripting (UXSS) vulnerability in Vimium Extension 1.66 and earlier allows remote attacke

Q: How do I fix CVE-2021-37518?

vimium: upgrade to newer than 1.66. Exact commands for each OS are on this page.

Q: Is CVE-2021-37518 being exploited?

CVE-2021-37518 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-37518 affect?

CVE-2021-37518 affects vimium. Severity is medium (CVSS 6.1). Universal Cross Site Scripting (UXSS) vulnerability in Vimium Extension 1.66 and earlier allows remote attackers to run arbitrary code via omnibar feature.

Q: How urgent is CVE-2021-37518?

Priority 39/100. Public exploit reference

Routine

MEDIUM 6.1UPGRADE

CVE-2021-37518 is a medium-severity flaw (CVSS 6.1) affecting vimium. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Universal Cross Site Scripting (UXSS) vulnerability in Vimium Extension 1.66 and earlier allows remote attackers to run arbitrary code via omnibar feature.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.7% (top 48%)
CISA exploited list	No
Weakness	CWE-79
Published	2023-02-03
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: vimium project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-02-03 18:15 UTCPublished CVE record published
2026-06-17 04:00 UTCUpdated Record last modified

vimium project vimium UPGRADE

Affected: <= 1.66

Fixed in: newer than 1.66

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy vimium || rpm -q vimium || vimium --version

2. UPGRADE to newer than 1.66 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade vimium

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade vimium

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-37518?

vimium: upgrade to newer than 1.66. Exact commands for each OS are on this page.

Is CVE-2021-37518 being exploited?

CVE-2021-37518 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-37518 affect?

CVE-2021-37518 affects vimium. Severity is medium (CVSS 6.1). Universal Cross Site Scripting (UXSS) vulnerability in Vimium Extension 1.66 and earlier allows remote attackers to run arbitrary code via omnibar feature.

How urgent is CVE-2021-37518?

Priority 39/100. Public exploit reference

References

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