CVE-2024-9396Network attack vector

Memory corruption via repeated transferable deserialization

Published Oct 1, 2024 · Updated Oct 1, 2024

Memory corruption in Firefox before 131, Firefox ESR before 128.3, and Thunderbird before 131 allows remote attackers to corrupt memory. The JavaScript engine permits a structured-clone buffer containing transferable objects to be deserialized more than once, violating the one-time transfer invariant. Reaching the flaw requires reuse of such a buffer; Mozilla found no browser trigger and states that exploitability remains unknown, while Thunderbird disables scripting when reading email.

CVSS severity8.8
High
EPSS probability0.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Firefox before 131, Firefox ESR before 128.3, and Thunderbird before 131 allows remote attackers to corrupt memory. The JavaScript engine permits a structured-clone buffer containing transferable objects to be deserialized more than once, violating the one-time transfer invariant. Reaching the flaw requires reuse of such a buffer; Mozilla found no browser trigger and states that exploitability remains unknown, while Thunderbird disables scripting when reading email.

The record

CVE
CVE-2024-9396
Published
Oct 1, 2024
Updated
Oct 1, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-119
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 1, 2024CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 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=0 <131
  2. Affected versionversion=unspecified <131

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=0 <131; version=unspecified <131
Mozilla · Thunderbirdversion=0 <128.3; version=0 <131; version=unspecified <128.3; version=unspecified <131
Mozilla · Firefox ESRversion=0 <128.3; version=unspecified <128.3

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 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-119Improper Restriction of Operations within the Bounds of a Memory Buffer

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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