CVE-2021-43531

When a user loaded a Web Extensions context menu, the Web Extension could access the post-redirect URL of the element clicked. If the Web Extension lacked the WebRequest permission for the hosts involved in the redirect, this would be a same-origin-violation leaking data the Web Extension should have access to. This was fixed to provide the pre-redirect URL. This is related to CVE-2021-43532 but in the context of Web Extensions. This vulnerability affects Firefox < 94.

Weakness

The product does not properly verify that the source of data or communication is valid.

Affected Software

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/111.html
• https://cwe.mitre.org/data/definitions/141.html
• https://cwe.mitre.org/data/definitions/142.html
• https://cwe.mitre.org/data/definitions/160.html
• https://cwe.mitre.org/data/definitions/21.html
• https://cwe.mitre.org/data/definitions/384.html
• https://cwe.mitre.org/data/definitions/385.html
• https://cwe.mitre.org/data/definitions/386.html
• https://cwe.mitre.org/data/definitions/387.html
• https://cwe.mitre.org/data/definitions/388.html
• https://cwe.mitre.org/data/definitions/510.html
• https://cwe.mitre.org/data/definitions/59.html
• https://cwe.mitre.org/data/definitions/60.html
• https://cwe.mitre.org/data/definitions/75.html
• https://cwe.mitre.org/data/definitions/76.html
• https://cwe.mitre.org/data/definitions/89.html

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1659155
• https://www.mozilla.org/security/advisories/mfsa2021-48/