CVE-2020-35112

Name: CVE-2020-35112
Creator: NVD / NIST
Published: 2021-01-07T14:15:12.517+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 8.8/10EPSS 1.29%

Last modified Jun 17, 2026

CVE-2020-35112 is a high-severity vulnerability rated 8.8/10 on the CVSS scale. If a user downloaded a file lacking an extension on Windows, and then "Open"-ed it from the downloads panel, if there was an executable file in the downloads directory with the same name but with an executable extension (such as .bat or .exe) that executable would have been launched instead. *Note: This issue only affected Windows operating systems. EPSS estimates a 1.29% chance of exploitation in the next 30 days.

Description

If a user downloaded a file lacking an extension on Windows, and then "Open"-ed it from the downloads panel, if there was an executable file in the downloads directory with the same name but with an executable extension (such as .bat or .exe) that executable would have been launched instead. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.*. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

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

1.29%

66.5th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 84.0
Mozilla	Firefox Esr	< 78.6.0
Mozilla	Thunderbird	< 78.6.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1661365Permissions Required
https://www.mozilla.org/security/advisories/mfsa2020-54/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-55/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-56/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1661365Permissions Required
https://www.mozilla.org/security/advisories/mfsa2020-54/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-55/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-56/Vendor Advisory

Timeline

Published: Jan 7, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-35112?

How severe is CVE-2020-35112?

CVE-2020-35112 has a CVSS score of 8.8/10 (HIGH severity). The EPSS model estimates a 1.29% probability of exploitation in the next 30 days.

How do I fix CVE-2020-35112?

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-2020-35112?

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

Scan your code now

Source: NVD / NIST