CVE-2020-15667

Name: CVE-2020-15667
Creator: NVD / NIST
Published: 2020-10-01T19:15:13.267+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 1.56%

Last modified Jun 17, 2026

CVE-2020-15667 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. When processing a MAR update file, after the signature has been validated, an invalid name length could result in a heap overflow, leading to memory corruption and potentially arbitrary code execution. Within Firefox as released by Mozilla, this issue is only exploitable with the Mozilla-controlled signing key. EPSS estimates a 1.56% chance of exploitation in the next 30 days.

Description

When processing a MAR update file, after the signature has been validated, an invalid name length could result in a heap overflow, leading to memory corruption and potentially arbitrary code execution. Within Firefox as released by Mozilla, this issue is only exploitable with the Mozilla-controlled signing key. This vulnerability affects Firefox < 80.

Metrics

CVSS 3.1

8.8/10

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

EPSS Probability

1.56%

72.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 80.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1653371Issue Tracking, Permissions Required, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-36/Release Notes, Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1653371Issue Tracking, Permissions Required, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-36/Release Notes, Vendor Advisory

Timeline

Published: Oct 1, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-15667?

How severe is CVE-2020-15667?

CVE-2020-15667 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.56% probability of exploitation in the next 30 days.

How do I fix CVE-2020-15667?

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-2020-15667?

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

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Source: NVD / NIST