CVE-2026-74974Network attack vector

Cross-origin isolation bypass

Published Aug 18, 2026 · Updated Aug 18, 2026

Same-origin policy bypass in ImageLib in Mozilla Firefox and Thunderbird allows remote attackers to violate origin isolation via unspecified vectors. Mozilla has not published the ImageLib code locus, triggering input, or incorrect operation that causes the policy failure. Exploitation requires user interaction; the public record does not identify what data can be read or changed across origins.

CVSS severity6.1
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Same-origin policy bypass in ImageLib in Mozilla Firefox and Thunderbird allows remote attackers to violate origin isolation via unspecified vectors. Mozilla has not published the ImageLib code locus, triggering input, or incorrect operation that causes the policy failure. Exploitation requires user interaction; the public record does not identify what data can be read or changed across origins.

The record

CVE
CVE-2026-74974
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

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

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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

6.1Oracle LinuxCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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

No sourced classifications are available.

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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