CVE-2020-26967

CVE-2020-26967 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

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.

Frequently asked questions

What is CVE-2020-26967?
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.
How severe is CVE-2020-26967?
CVE-2020-26967 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2020-26967 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (54th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-26967?
CVE-2020-26967 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-26967?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-26967 published?
CVE-2020-26967 was published on 2020-12-09 and last updated on 2026-06-17.

References

Affected products (1)

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