CVE-2026-74976Network attack vector

Data disclosure via JIT miscompilation

Published Aug 18, 2026 · Updated Aug 19, 2026

JIT miscompilation in Mozilla Firefox and Thunderbird allows remote attackers to disclose data through crafted web content. Mozilla identifies the JavaScript Engine JIT component as the locus, but the restricted bug report leaves the incorrect optimization and triggering input undisclosed. Exploitation requires user interaction, and the published assessment limits impact to confidentiality without integrity or availability loss.

CVSS severity6.5
Medium
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

JIT miscompilation in Mozilla Firefox and Thunderbird allows remote attackers to disclose data through crafted web content. Mozilla identifies the JavaScript Engine JIT component as the locus, but the restricted bug report leaves the incorrect optimization and triggering input undisclosed. Exploitation requires user interaction, and the published assessment limits impact to confidentiality without integrity or availability loss.

The record

CVE
CVE-2026-74976
Published
Aug 18, 2026
Updated
Aug 19, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-843, CWE-733
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5CISA ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
3.4Red HatCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/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 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-843Access of Resource Using Incompatible Type ('Type Confusion')
CWE-733Compiler Optimization Removal or Modification of Security-critical Code

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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