CVE-2024-1556Network attack vector

Browser crash via wrong profiler pointer check

Published Feb 20, 2024 · Updated Nov 12, 2024

Invalid memory access in Firefox before 123 allows attackers to crash a profiled browser via data recorded by the built-in profiler. InChunkPointer::ShouldPointAtValidBlock() advances a copied pointer by an entry size, then mistakenly tests the original pointer for null, allowing an out-of-bounds pointer to pass validation. Reachability requires the profiler to be running, and Mozilla's public bug record establishes no demonstrated webpage trigger or impact beyond service interruption.

CVSS severity6.5
Medium
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Invalid memory access in Firefox before 123 allows attackers to crash a profiled browser via data recorded by the built-in profiler. InChunkPointer::ShouldPointAtValidBlock() advances a copied pointer by an entry size, then mistakenly tests the original pointer for null, allowing an out-of-bounds pointer to pass validation. Reachability requires the profiler to be running, and Mozilla's public bug record establishes no demonstrated webpage trigger or impact beyond service interruption.

The record

CVE
CVE-2024-1556
Published
Feb 20, 2024
Updated
Nov 12, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-754, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 20, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 12, 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=unspecified <123

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <123

Published CVSS scores

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

Weakness, pattern, technique

CWE-754Improper Check for Unusual or Exceptional Conditions
T1499.004Application or System Exploitation

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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