CVE-2025-6429

Summary

Firefox could have incorrectly parsed a URL and rewritten it to the youtube.com domain when parsing the URL specified in an embed tag. This could have bypassed website security checks that restricted which domains users were allowed to embed. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.

Affected Software

VendorProductVersion RangeStatus
MozillaFirefox128.12 <= 128.*unaffected
MozillaFirefox140 <= *unaffected
MozillaThunderbird128.12 <= 128.*unaffected
MozillaThunderbird140 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References