CVE-2024-29943Known exploitationPublic exploitNetwork attack vector

Memory corruption via incorrect JIT range analysis

Published Mar 22, 2024 · Updated Feb 13, 2025

Out-of-bounds access in Firefox before 124.0.1 allows remote attackers to read or write memory via crafted JavaScript. MObjectKeysLength::computeRange supplies an incorrect range, causing the JIT optimizer to eliminate a required bounds check. Execution requires Firefox to process attacker-controlled JavaScript; the resulting memory corruption was used in a Pwn2Own exploit chain.

CVSS severity9.8
Critical
EPSS probability22.93%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Firefox before 124.0.1 allows remote attackers to read or write memory via crafted JavaScript. MObjectKeysLength::computeRange supplies an incorrect range, causing the JIT optimizer to eliminate a required bounds check. Execution requires Firefox to process attacker-controlled JavaScript; the resulting memory corruption was used in a Pwn2Own exploit chain.

The record

CVE
CVE-2024-29943
Published
Mar 22, 2024
Updated
Feb 13, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-787, CWE-125, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 22, 2024CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record 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 <124.0.1
  2. Affected versionversion=unspecified <124.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=0 <124.0.1; version=unspecified <124.0.1

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-125Out-of-bounds Read
T1203Exploitation for Client Execution

Public exploit references

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

Reported exploitation

Technologies

Your stack

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Your stack

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