Cyber Resilience

CVE-2024-29943

Memory Safety in Mozilla Firefox ≤ 124.0.1

Published
22 March 2024
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.23 98th percentile
Risk Priority 93 floored blend · peak EPSS

Summary

CVE-2024-29943 is a critical-severity Out-of-bounds Read (CWE-125) vulnerability in Mozilla Firefox. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2024-29943 is an out-of-bounds read or write vulnerability affecting JavaScript objects in Firefox versions prior to 124.0.1. The flaw stems from incorrect elimination of range-based bounds checks, which permits memory access beyond the intended object boundaries and is tracked under CWE-125 and CWE-787. It carries a CVSS 3.1 score of 9.8, reflecting network-exploitable conditions with no required authentication or user interaction.

An unauthenticated remote attacker can trigger the issue by serving malicious JavaScript that reaches the flawed bounds-check logic, resulting in arbitrary memory corruption. Successful exploitation can yield full confidentiality, integrity, and availability impact, including the potential for remote code execution within the browser process.

Mozilla’s advisory MFSA2024-15 and the corresponding Bugzilla entry 1886849 indicate that the vulnerability is resolved in Firefox 124.0.1; users are advised to apply the update immediately. The referenced oss-security postings reiterate the same patch guidance for affected Mozilla products.

The associated EPSS score currently stands at 0.5386 with a recorded peak of 0.5737, indicating sustained moderate-to-high exploitation interest following disclosure.

EU & UK References

Vulnerability Data

An attacker was able to perform an out-of-bounds read or write on a JavaScript object by fooling range-based bounds check elimination. This vulnerability affects Firefox < 124.0.1.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-49709Same product: Mozilla Firefox
CVE-2023-23606Same product: Mozilla Firefox
CVE-2023-5731Same product: Mozilla Firefox
CVE-2024-5695Same product: Mozilla Firefox
CVE-2023-32209Same product: Mozilla Firefox
CVE-2024-2615Same product: Mozilla Firefox
CVE-2023-37212Same product: Mozilla Firefox
CVE-2025-1414Same product: Mozilla Firefox
CVE-2023-28177Same product: Mozilla Firefox
CVE-2024-1557Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 124.0.1

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation directly finds out-of-bounds read flaws through static analysis, fuzzing, and dynamic bounds checks.

Requiring documented secure-development standards and tools can mandate bounds-checked coding practices that avoid the weakness.

Secure engineering principles require bounds checking and memory-safe constructs that stop out-of-bounds reads from being introduced.

Process isolation confines the effects of an out-of-bounds read to the compromised process.

Input validation rejects malformed indices or lengths that would otherwise cause reads outside buffer bounds.

Memory-protection mechanisms limit the exploitability and blast radius of a successful out-of-bounds write.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices such as bounds checking and memory-safe languages directly prevent out-of-bounds reads.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing out-of-bounds read flaws.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development and acceptance includes fuzzing and static analysis that detect out-of-bounds read defects before release.

A.8.15 Logging partial match
finds

Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.

prevents

Secure development life cycle mandates input validation and bounds checking that directly prevent out-of-bounds reads.

prevents

Application security requirements include explicit bounds and memory-safety specifications that mitigate buffer over-reads.

prevents

Secure system architecture and engineering principles require memory-safe design patterns and runtime protections against out-of-bounds access.

prevents

Secure coding standards explicitly forbid unsafe pointer arithmetic and mandate bounds-checked reads, eliminating CWE-125.

References