CVE-2021-23986

Description

A malicious extension with the 'search' permission could have installed a new search engine whose favicon referenced a cross-origin URL. The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cross-origin permissions. This cross-origin request was made without cookies, so the sensitive information disclosed by the violation was limited to local-network resources or resources that perform IP-based authentication. This vulnerability affects Firefox < 87.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.05%
Vendor Advisory mozilla.org Vendor Advisory mozilla.org
Affected: Mozilla Firefox
Published at:
Updated at:

References

Link Tags
https://www.mozilla.org/security/advisories/mfsa2021-10/ vendor advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1692623 issue tracking permissions required vendor advisory

Frequently Asked Questions

What is the severity of CVE-2021-23986?
CVE-2021-23986 has been scored as a medium severity vulnerability.
How to fix CVE-2021-23986?
To fix CVE-2021-23986, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-23986 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-23986 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-23986?
CVE-2021-23986 affects Mozilla Firefox.
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