CVE-2021-23982

Name: CVE-2021-23982
Creator: NVD / NIST
Published: 2021-03-31T14:15:19+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.74%

Last modified Jun 17, 2026

CVE-2021-23982 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. Using techniques that built on the slipstream research, a malicious webpage could have scanned both an internal network's hosts as well as services running on the user's local machine utilizing WebRTC connections. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.. EPSS estimates a 0.74% chance of exploitation in the next 30 days.

Description

Using techniques that built on the slipstream research, a malicious webpage could have scanned both an internal network's hosts as well as services running on the user's local machine utilizing WebRTC connections. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

0.74%

50.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-326

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 87.0
Mozilla	Firefox Esr	< 78.9
Mozilla	Thunderbird	< 78.9

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1677046Issue Tracking, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-10/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-11/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-12/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1677046Issue Tracking, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-10/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-11/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2021-12/Vendor Advisory

Timeline

Published: Mar 31, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-23982?

How severe is CVE-2021-23982?

CVE-2021-23982 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.74% probability of exploitation in the next 30 days.

How do I fix CVE-2021-23982?

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-2021-23982?

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

Scan your code now

Source: NVD / NIST