CVE-2024-7527Network attack vector

Memory corruption via late garbage-collection marking

Published Aug 6, 2024 · Updated Mar 18, 2025

Use-after-free in Firefox, Firefox ESR, and Thunderbird allows remote attackers to corrupt memory through browser-like content. The faulty mark-to-sweep sequence collects the nursery after draining the mark stack, letting a finalization post barrier add marking work before sweeping. Normal browsing reaches the flaw; scripting is disabled while Thunderbird reads email, limiting that product's exposure to browser-like contexts.

CVSS severity8.8
High
EPSS probability0.61%
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 Firefox, Firefox ESR, and Thunderbird allows remote attackers to corrupt memory through browser-like content. The faulty mark-to-sweep sequence collects the nursery after draining the mark stack, letting a finalization post barrier add marking work before sweeping. Normal browsing reaches the flaw; scripting is disabled while Thunderbird reads email, limiting that product's exposure to browser-like contexts.

The record

CVE
CVE-2024-7527
Published
Aug 6, 2024
Updated
Mar 18, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 6, 2024CVE publishedPublication date reported by the CVE source.
  2. Mar 18, 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 <129
  2. Affected versionversion=unspecified <129

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=0 <129; version=unspecified <129
Mozilla · Thunderbirdversion=0 <115.14; version=0 <128.1; version=unspecified <115.14; version=unspecified <128.1
Mozilla · Firefox ESRversion=0 <115.14; version=0 <128.1; version=unspecified <115.14; version=unspecified <128.1

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

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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