CVE-2024-4769Network attack vector

Cross-origin information disclosure via Worker error oracle

Published May 14, 2024 · Updated Feb 13, 2025

Firefox before 126 and Firefox ESR or Thunderbird before 115.11 allow remote attackers to infer cross-origin response content types. The DOM Workers script loader emits distinct load-error messages for application/javascript and non-script responses instead of normalizing them. A hostile origin must cause a Web Worker import; the oracle reveals only the target response's script-versus-non-script type, and Thunderbird mail reading disables scripting.

CVSS severity5.9
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Firefox before 126 and Firefox ESR or Thunderbird before 115.11 allow remote attackers to infer cross-origin response content types. The DOM Workers script loader emits distinct load-error messages for application/javascript and non-script responses instead of normalizing them. A hostile origin must cause a Web Worker import; the oracle reveals only the target response's script-versus-non-script type, and Thunderbird mail reading disables scripting.

The record

CVE
CVE-2024-4769
Published
May 14, 2024
Updated
Feb 13, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-351
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 14, 2024CVE publishedPublication date reported by the CVE source.
  2. Feb 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=- <126
  2. Affected versionversion=unspecified <126

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=- <126; version=unspecified <126
Mozilla · Thunderbirdversion=- <115.11; version=unspecified <115.11
Mozilla · Firefox ESRversion=- <115.11; version=unspecified <115.11

Published CVSS scores

5.9CISA-ADPCVSS:3.1/AV:N/AC:H/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.

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-351Insufficient Type Distinction

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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