CVE-2020-26967

6.5 mediumEPSS 0.9%

Medium (6.5) in mozilla firefox. EPSS 0.9% chance of exploitation in the next 30 days.

When listening for page changes with a Mutation Observer, a malicious web page could confuse Firefox Screenshots into interacting with elements other than those that it injected into the page. This would lead to internal errors and unexpected behavior in the Screenshots code. This vulnerability affects Firefox < 83.

Severity

CVSS 3.1

6.5 medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

EPSS: 0.9% chance of exploitation in the next 30 days; higher than 58% of CVEs (scores of 2026-10-31)
Published: 2020-12-09
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

mozilla:firefox

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1665820
https://www.mozilla.org/security/advisories/mfsa2020-50/
https://bugzilla.mozilla.org/show_bug.cgi?id=1665820
https://www.mozilla.org/security/advisories/mfsa2020-50/

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