Resource exhaustion in Cyberfox Web Browser

CVE-2021-47784

Cyberfox Web Browser 52.9.1 contains a denial of service vulnerability that allows attackers to crash the application by overflowing the search bar with excessive data. Attackers can generate a 9,000,000 byte payload and paste it into the search bar to trigger an application crash.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.002 (12.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 13th percentile — 12.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2021-47784: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-47784?
CVE-2021-47784 is a high-severity vulnerability in Cyberfox Web Browser, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-01-15.
How severe is CVE-2021-47784?
High severity. CVSS v3 base score is 7.5 out of 10.