Script element events leaked cross-origin resource status

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-5266
StatePUBLISHED
Assignermozilla
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-05-27 13:15:22 UTC
Updated2026-04-13 15:17:04 UTC
DescriptionScript elements loading cross-origin resources generated load and error events which leaked information enabling XS-Leaks attacks. This vulnerability was fixed in Firefox 139, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.

Risk And Classification

Primary CVSS: v3.1 4.3 MEDIUM from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

EPSS: 0.004340000 probability, percentile 0.628840000 (date 2026-04-15)

Problem Types: CWE-200 | CWE-200 CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED4.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary4.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Mozilla Firefox All All All All
Application Mozilla Firefox All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mozilla Firefox unaffected 128.11 128.* rpm Not specified
CNA Mozilla Firefox unaffected 139 * rpm Not specified
CNA Mozilla Thunderbird unaffected 128.11 128.* rpm Not specified
CNA Mozilla Thunderbird unaffected 139 * rpm Not specified

References

ReferenceSourceLinkTags
lists.debian.org/debian-lts-announce/2025/05/msg00043.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org
lists.debian.org/debian-lts-announce/2025/05/msg00046.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org
www.mozilla.org/security/advisories/mfsa2025-42 [email protected] www.mozilla.org Vendor Advisory
www.mozilla.org/security/advisories/mfsa2025-45 [email protected] www.mozilla.org
www.mozilla.org/security/advisories/mfsa2025-44 [email protected] www.mozilla.org Vendor Advisory
www.mozilla.org/security/advisories/mfsa2025-46 [email protected] www.mozilla.org
bugzilla.mozilla.org/show_bug.cgi [email protected] bugzilla.mozilla.org Permissions Required
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Jakub Szymsza (en)

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