CVE-2022-40956

CVE-2022-40956 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

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.

Frequently asked questions

What is CVE-2022-40956?
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.
How severe is CVE-2022-40956?
CVE-2022-40956 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2022-40956 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-40956?
CVE-2022-40956 primarily affects Mozilla Firefox. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2022-40956?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2022-40956 published?
CVE-2022-40956 was published on 2022-12-22 and last updated on 2026-06-17.

References

Affected products (3)

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