CVE-2020-26955

Name: CVE-2020-26955
Creator: NVD / NIST
Published: 2020-12-09T01:15:12.893+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 0.82%

Last modified Jun 17, 2026

CVE-2020-26955 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. When a user downloaded a file in Firefox for Android, if a cookie is set, it would have been re-sent during a subsequent file download operation on the same domain, regardless of whether the original and subsequent request were in private and non-private browsing modes. *Note: This issue only affected Firefox for Android. EPSS estimates a 0.82% chance of exploitation in the next 30 days.

Description

When a user downloaded a file in Firefox for Android, if a cookie is set, it would have been re-sent during a subsequent file download operation on the same domain, regardless of whether the original and subsequent request were in private and non-private browsing modes. *Note: This issue only affected Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 83.

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

0.82%

52.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-565

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 83.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1663261Issue Tracking, Permissions Required, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-50/Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1663261Issue Tracking, Permissions Required, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-50/Vendor Advisory

Timeline

Published: Dec 9, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26955?

How severe is CVE-2020-26955?

CVE-2020-26955 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.82% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26955?

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-2020-26955?

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

Scan your code now

Source: NVD / NIST