CVE-2024-2608Public exploit

Out-of-bounds write via encoded-string length overflow

Published Mar 19, 2024 · Updated Mar 13, 2025

Memory corruption in Mozilla Firefox before 124, Firefox ESR before 115.9, and Thunderbird before 115.9 allows attackers to write out of bounds. DOM serializer functions add untrusted string and escape-sequence lengths with unchecked 32-bit arithmetic, so StringBuilder::ToString allocates a buffer far smaller than the encoded output. Triggering requires combined expanded lengths of at least 0x100000000; ordinary Thunderbird mail reading disables scripting.

CVSS severity8.4
High
EPSS probability0.39%
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 Mozilla Firefox before 124, Firefox ESR before 115.9, and Thunderbird before 115.9 allows attackers to write out of bounds. DOM serializer functions add untrusted string and escape-sequence lengths with unchecked 32-bit arithmetic, so StringBuilder::ToString allocates a buffer far smaller than the encoded output. Triggering requires combined expanded lengths of at least 0x100000000; ordinary Thunderbird mail reading disables scripting.

The record

CVE
CVE-2024-2608
Published
Mar 19, 2024
Updated
Mar 13, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-680, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 19, 2024CVE publishedPublication date reported by the CVE source.
  2. Mar 13, 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 <124
  2. Affected versionversion=unspecified <124

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=0 <124; version=unspecified <124
Mozilla · Thunderbirdversion=0 <115.9; version=unspecified <115.9
Mozilla · Firefox ESRversion=0 <115.9; version=unspecified <115.9

Published CVSS scores

8.4CISA-ADPCVSS:3.1/AV:L/AC:L/PR:N/UI:N/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-680Integer Overflow to Buffer Overflow
T1203Exploitation for Client Execution

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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