CVE-2025-4088Public exploitNetwork attack vector

Cross-site request forgery via storage access API redirects

Published Apr 29, 2025 · Updated Apr 13, 2026

Cross-site request forgery in Mozilla Firefox and Thunderbird before 138 allows remote attackers to send credentialed cross-origin requests. A cross-origin fetch redirect retains the storage-access flag, causing the browser to attach unpartitioned cookies after crossing origins. Exploitation requires an embedded site to receive Storage Access API permission; the result is an attacker-directed authenticated action at that site.

CVSS severity6.5
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in Mozilla Firefox and Thunderbird before 138 allows remote attackers to send credentialed cross-origin requests. A cross-origin fetch redirect retains the storage-access flag, causing the browser to attach unpartitioned cookies after crossing origins. Exploitation requires an embedded site to receive Storage Access API permission; the result is an attacker-directed authenticated action at that site.

The record

CVE
CVE-2025-4088
Published
Apr 29, 2025
Updated
Apr 13, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-352
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 13, 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:N/S:U/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.

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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 exploitPublished

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)

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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