CVE-2024-5694Network attack vector

Heap-memory disclosure via stale JavaScript string reference

Published Jun 11, 2024 · Updated Mar 14, 2025

Use-after-free in Mozilla Firefox before 127 allows remote attackers to read memory from the JavaScript string heap. AutoStableStringChars failed to retain the owning JavaScript string while JSONParser used its character buffer, leaving a stale reference after release. Triggering requires attacker-controlled JavaScript; observed accesses are reads only, and the address is confined to the string-heap partition and is not controllable.

CVSS severity7.5
High
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

Use-after-free in Mozilla Firefox before 127 allows remote attackers to read memory from the JavaScript string heap. AutoStableStringChars failed to retain the owning JavaScript string while JSONParser used its character buffer, leaving a stale reference after release. Triggering requires attacker-controlled JavaScript; observed accesses are reads only, and the address is confined to the string-heap partition and is not controllable.

The record

CVE
CVE-2024-5694
Published
Jun 11, 2024
Updated
Mar 14, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-416, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 11, 2024CVE publishedPublication date reported by the CVE source.
  2. Mar 14, 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 <127

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <127

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1189Drive-by Compromise

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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