CVE-2021-1855

CVE-2021-1855 is a medium-severity vulnerability in Apple Macos 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

A logic issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.3. A malicious website may be able to force unnecessary network connections to fetch its favicon.

Frequently asked questions

What is CVE-2021-1855?
A logic issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.3. A malicious website may be able to force unnecessary network connections to fetch its favicon.
How severe is CVE-2021-1855?
CVE-2021-1855 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 no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-1855 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1855?
CVE-2021-1855 affects Apple Macos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-1855?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-1855 published?
CVE-2021-1855 was published on 2021-09-08 and last updated on 2026-06-17.

References

Affected products (1)

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