CVE-2022-40956 Cross-site scripting in Firefox
Attackers can bypass CSP base-uri restrictions by injecting HTML base elements, potentially enabling cross-site scripting attacks in Firefox and Thunderbird.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2022-40956?
CVE-2022-40956 is a medium-severity cross-site scripting vulnerability in Mozilla Firefox, published on 22 Dec 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
When injecting an HTML base element, some requests would ignore the CSP's base-uri settings and accept the injected element's base instead. This vulnerability affects Firefox ESR < 102.3, Thunderbird < 102.3, and Firefox < 105.
Weakness: CWE-79
Which versions are affected by CVE-2022-40956?
It affects 3 products.
Products include Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird.
How do I fix CVE-2022-40956?
Upgrade to a fixed version.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2022-40956 being exploited?
There is no known exploitation of CVE-2022-40956 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as DEBIAN-CVE-2022-40956, GHSA-74v3-gjvq-vv7f, UBUNTU-CVE-2022-40956.