What’s Vulnerable › Vulnerabilities

CVE-2022-40956

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-12-22 · updated 2026-06-17
• Weakness: CWE-79

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.

Affected products

• Mozilla Firefox: before 105.0 — fixed in 105.0
• Mozilla Firefox ESR: before 102.3 — fixed in 102.3
• Mozilla Thunderbird: before 102.3 — fixed in 102.3

How to fix

Upgrade to a fixed version: Mozilla Firefox 105.0; Mozilla Firefox ESR 102.3; Mozilla Thunderbird 102.3. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1770094
• https://www.mozilla.org/security/advisories/mfsa2022-40/
• https://www.mozilla.org/security/advisories/mfsa2022-41/
• https://www.mozilla.org/security/advisories/mfsa2022-42/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1770094
• https://www.mozilla.org/security/advisories/mfsa2022-40/
• https://www.mozilla.org/security/advisories/mfsa2022-41/
• https://www.mozilla.org/security/advisories/mfsa2022-42/

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