CVE-2024-0754Public exploitNetwork attack vector

Browser crash via mishandled WebAssembly tail calls

Published Jan 23, 2024 · Updated May 22, 2025

A DevTools WebAssembly flaw in Mozilla Firefox before 122 allows remote attackers to crash the browser via a crafted WASM source file. The debugger uses the wrong LeaveFrame marker for tail calls and tracks reference-type results that must be discarded, ending in invalid JSObject::getClass access. Exploitation requires a user to load the crafted source in DevTools, and the demonstrated consequence is a browser crash.

CVSS severity6.5
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A DevTools WebAssembly flaw in Mozilla Firefox before 122 allows remote attackers to crash the browser via a crafted WASM source file. The debugger uses the wrong LeaveFrame marker for tail calls and tracks reference-type results that must be discarded, ending in invalid JSObject::getClass access. Exploitation requires a user to load the crafted source in DevTools, and the demonstrated consequence is a browser crash.

The record

CVE
CVE-2024-0754
Published
Jan 23, 2024
Updated
May 22, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-248
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 23, 2024CVE publishedPublication date reported by the CVE source.
  2. May 22, 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=unspecified <122

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <122

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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.

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-248Uncaught Exception

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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