CVE-2024-3857Public exploit

Application crash via JIT argument rectification

Published Apr 16, 2024 · Updated Aug 1, 2024

Use-after-free in Mozilla Firefox before 125, Firefox ESR before 115.10, and Thunderbird before 115.10 allows attackers to crash the application. The WebAssembly JIT entry stub invokes the arguments rectifier for a parameter mismatch and emits an invalid pointer that garbage collection later dereferences. Reaching the defect requires JIT execution with mismatched function arguments; Thunderbird mail reading disables scripting, limiting exposure to browser-like contexts.

CVSS severity7.8
High
EPSS probability0.24%
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 Mozilla Firefox before 125, Firefox ESR before 115.10, and Thunderbird before 115.10 allows attackers to crash the application. The WebAssembly JIT entry stub invokes the arguments rectifier for a parameter mismatch and emits an invalid pointer that garbage collection later dereferences. Reaching the defect requires JIT execution with mismatched function arguments; Thunderbird mail reading disables scripting, limiting exposure to browser-like contexts.

The record

CVE
CVE-2024-3857
Published
Apr 16, 2024
Updated
Aug 1, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-416, T1203
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 16, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 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 vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

Mozilla · Firefoxversion=0 <125; version=unspecified <125
Mozilla · Thunderbirdversion=0 <115.10; version=unspecified <115.10
Mozilla · Firefox ESRversion=0 <115.10; version=unspecified <115.10

Published CVSS scores

7.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

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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