CVE-2025-8038Public exploitNetwork attack vector

Content Security Policy bypass via ignored frame paths

Published Jul 22, 2025 · Updated Jul 29, 2026

CSP bypass in Mozilla Firefox and Thunderbird before 141 and ESR editions before 140.1 allows remote attackers to escape frame path limits. The frame-src host-source matcher treated frame navigations as redirects and consequently ignored the allowed source path during same-origin navigation. Exploitation requires content rendered in an affected client and a policy relying on an origin-plus-path restriction; the bypass loads unintended framed content and enables site-script attacks.

CVSS severity9.8
Critical
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSP bypass in Mozilla Firefox and Thunderbird before 141 and ESR editions before 140.1 allows remote attackers to escape frame path limits. The frame-src host-source matcher treated frame navigations as redirects and consequently ignored the allowed source path during same-origin navigation. Exploitation requires content rendered in an affected client and a policy relying on an origin-plus-path restriction; the bypass loads unintended framed content and enables site-script attacks.

The record

CVE
CVE-2025-8038
Published
Jul 22, 2025
Updated
Jul 29, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-345, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 22, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 29, 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

5.1SUSECVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
5.4SUSECVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
9.8CISA-ADPCVSS:3.1/AV:N/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 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 exploitPublished

Weakness, pattern, technique

CWE-345Insufficient Verification of Data Authenticity
T1189Drive-by Compromise

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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