CVE-2021-3377

Name: CVE-2021-3377
Creator: NVD / NIST
Published: 2021-03-05T21:15:13.263+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 8.00%

Last modified Jun 17, 2026

CVE-2021-3377 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. The npm package ansi_up converts ANSI escape codes into HTML. In ansi_up v4, ANSI escape codes can be used to create HTML hyperlinks. EPSS estimates a 8.00% chance of exploitation in the next 30 days.

Description

The npm package ansi_up converts ANSI escape codes into HTML. In ansi_up v4, ANSI escape codes can be used to create HTML hyperlinks. Due to insufficient URL sanitization, this feature is affected by a cross-site scripting (XSS) vulnerability. This issue is fixed in v5.0.0.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

8.00%

94.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions
Ansi Up Project	Ansi Up	< 5.0.0

References

https://doyensec.com/resources/Doyensec_Advisory_ansi_up4_XSS.pdfExploit, Third Party Advisory
https://github.com/drudru/ansi_up/commit/c8c726ed1db979bae4f257b7fa41775155ba2e27Patch, Third Party Advisory
https://doyensec.com/resources/Doyensec_Advisory_ansi_up4_XSS.pdfExploit, Third Party Advisory
https://github.com/drudru/ansi_up/commit/c8c726ed1db979bae4f257b7fa41775155ba2e27Patch, Third Party Advisory
https://security.netapp.com/advisory/ntap-20241108-0002/

Timeline

Published: Mar 5, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3377?

How severe is CVE-2021-3377?

CVE-2021-3377 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 8.00% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3377?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3377?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST