CVE-2021-33850: There is a Cross-Site Scripting vulnerability in Microsoft Clarity version 0.3

This month

MEDIUM 5.4WATCHLISTDOWNGRADE

CVE-2021-33850 is a medium-severity flaw (CVSS 5.4) affecting clarity. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

There is a Cross-Site Scripting vulnerability in Microsoft Clarity version 0.3. The XSS payload executes whenever the user changes the clarity configuration in Microsoft Clarity version 0.3. The payload is stored on the configuring project Id page.

Why this priority

Public exploit reference
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	1.6% (top 24%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-11-19
Last modified	2026-06-17

Publisher (CNA): Cyber Security Works Pvt. Ltd. · Vendor: microsoft

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

Am I affected?

Timeline

2021-11-19 16:15 UTCPublished CVE record published
2026-06-17 03:55 UTCUpdated Record last modified

microsoft clarity DOWNGRADE

Affected: 0.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.3

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.3 (Debian / Ubuntu)

apt-cache madison clarity sudo apt install clarity=<VERSION_BEFORE_0.3> sudo apt-mark hold clarity

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list clarity sudo dnf downgrade clarity-<VERSION_BEFORE_0.3> sudo dnf versionlock add clarity

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2021-33850?

clarity: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-33850 being exploited?

CVE-2021-33850 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-2021-33850 affect?

CVE-2021-33850 affects clarity. Severity is medium (CVSS 5.4). There is a Cross-Site Scripting vulnerability in Microsoft Clarity version 0.3. The XSS payload executes whenever the user changes the clarity configuration in Microsoft Clarity version 0.3. The payload is stored on the configuring project

How urgent is CVE-2021-33850?

Priority 48/100. Public exploit reference; On your watchlist

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References

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