CVE-2024-3853

Browser crash via prematurely freed JavaScript realm

Published Apr 16, 2024 · Updated Oct 28, 2024

Use-after-free in Firefox before 125 allows attackers to crash the browser when garbage collection interrupts JavaScript realm initialization. Failed global-object creation leaves a live BaseShape pointing to a realm that incremental garbage collection has already destroyed. A later trace follows the dangling realm pointer to its global object and crashes the browser; no stronger demonstrated impact is public.

CVSS severity7.5
High
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Firefox before 125 allows attackers to crash the browser when garbage collection interrupts JavaScript realm initialization. Failed global-object creation leaves a live BaseShape pointing to a realm that incremental garbage collection has already destroyed. A later trace follows the dangling realm pointer to its global object and crashes the browser; no stronger demonstrated impact is public.

The record

CVE
CVE-2024-3853
Published
Apr 16, 2024
Updated
Oct 28, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-416, T1203
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 16, 2024CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 2024Record 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=0 <125
  2. Affected versionversion=unspecified <125

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=0 <125; version=unspecified <125

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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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