CVE-2021-47784Public exploit

Application crash via oversized search-bar input

Published Jan 15, 2026 · Updated Jan 15, 2026

Resource exhaustion in 8pecxstudios Cyberfox 52.9.1 allows local users to crash the browser via oversized search-bar input. The search bar processes a 9,000,000-byte string without an effective input or resource limit, terminating the browser. Exploitation requires an active user to paste the generated payload into a running Windows instance, and the demonstrated consequence is limited to an application crash.

CVSS severity6.7
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in 8pecxstudios Cyberfox 52.9.1 allows local users to crash the browser via oversized search-bar input. The search bar processes a 9,000,000-byte string without an effective input or resource limit, terminating the browser. Exploitation requires an active user to paste the generated payload into a running Windows instance, and the demonstrated consequence is limited to an application crash.

The record

CVE
CVE-2021-47784
Published
Jan 15, 2026
Updated
Jan 15, 2026
Vendor
8pecxstudios
Product
Cyberfox
Classifications
CWE-770, T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=52.9.1 (Possibly all versions)

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

8pecxstudios · Cyberfoxversion=52.9.1 (Possibly all versions)

Published CVSS scores

6.7VulnCheckCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
7.5VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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