CVE-2020-12401

Name: CVE-2020-12401
Creator: NVD / NIST
Published: 2020-10-08T14:15:11.25+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.7/10EPSS 0.31%

Last modified Jun 17, 2026

CVE-2020-12401 is a medium-severity vulnerability rated 4.7/10 on the CVSS scale. During ECDSA signature generation, padding applied in the nonce designed to ensure constant-time scalar multiplication was removed, resulting in variable-time execution dependent on secret data. This vulnerability affects Firefox < 80 and Firefox for Android < 80.. EPSS estimates a 0.31% chance of exploitation in the next 30 days.

Description

During ECDSA signature generation, padding applied in the nonce designed to ensure constant-time scalar multiplication was removed, resulting in variable-time execution dependent on secret data. This vulnerability affects Firefox < 80 and Firefox for Android < 80.

Metrics

CVSS 3.1

4.7/10

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

EPSS Probability

0.31%

22.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-203

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 80.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1631573Issue Tracking, Permissions Required, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2023/02/msg00021.html
https://www.mozilla.org/security/advisories/mfsa2020-36/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-39/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1631573Issue Tracking, Permissions Required, Vendor Advisory
https://lists.debian.org/debian-lts-announce/2023/02/msg00021.html
https://www.mozilla.org/security/advisories/mfsa2020-36/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-39/Vendor Advisory

Timeline

Published: Oct 8, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-12401?

How severe is CVE-2020-12401?

CVE-2020-12401 has a CVSS score of 4.7/10 (MEDIUM severity). The EPSS model estimates a 0.31% probability of exploitation in the next 30 days.

How do I fix CVE-2020-12401?

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-2020-12401?

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

Scan your code now

Source: NVD / NIST