How severe is CVE-2020-26962?

CVE-2020-26962 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-2020-26962 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-26962?

CVE-2020-26962 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-26962?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-26962 published?

CVE-2020-26962 was published on 2020-12-09 and last updated on 2026-06-17.

CVE-2020-26962

CVE-2020-26962 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-1021.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (48th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1021
Affected product: Mozilla Firefox
Published: 2020-12-09
Last modified: 2026-06-17

Description

Cross-origin iframes that contained a login form could have been recognized by the login autofill service, and populated. This could have been used in clickjacking attacks, as well as be read across partitions in dynamic first party isolation. This vulnerability affects Firefox < 83.

Frequently asked questions

What is CVE-2020-26962?: Cross-origin iframes that contained a login form could have been recognized by the login autofill service, and populated. This could have been used in clickjacking attacks, as well as be read across partitions in dynamic first party isolation. This vulnerability affects Firefox < 83.
How severe is CVE-2020-26962?: CVE-2020-26962 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-2020-26962 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (48th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-26962?: CVE-2020-26962 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-26962?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-26962 published?: CVE-2020-26962 was published on 2020-12-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*

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