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Vulnerabilities

Vulnerability · 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.

Published Jan 15, 2026 · catalog updated Jan 15, 2026 · Cyberfox Cyberfox Web Browser

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2021-47784. EPSS is 0.24%. Act only if a listed version of Cyberfox Cyberfox Web Browser is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.24%
Remediation
Vendor / distro source
Affected products
vendor Cyberfox Cyberfox Web Browser 52.9.1 (Possibly all versions)

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Cyberfox Cyberfox Web Browser 52.9.1 (Possibly all versions)52.9.1 (Possibly all versions)

How to fix CVE-2021-47784

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2021-47784. EPSS is 0.24%. Act only if a listed version of Cyberfox Cyberfox Web Browser is installed.

Which versions are affected?

Compare what you have installed with Cyberfox Cyberfox Web Browser 52.9.1 (Possibly all versions) 52.9.1 (Possibly all versions). Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.24%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 15, 2026 · EUVD

    Detected

    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.

  2. Jan 15, 2026 · EUVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2021-47784

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-47784

    30-day exploitation probability 0.24%

    first.org
  • EUVDVulnerability recordEUVD-2026-2764

    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 cras

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 6, 2026
  • EUVDNov 5, 2026
  • CVE.orgOct 30, 2026