Data stored in cookies for non-HTML content while browsing Incognito could be viewed after closing private tabs

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2025-10859
StatePUBLISHED
Assignermozilla
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-09-30 13:15:48 UTC
Updated2026-04-13 15:16:37 UTC
DescriptionCookie storage for non-HTML temporary documents was being shared incorrectly with normal browsing content, allowing information from private tabs to escape Incognito mode even after the user closed all tabs. This vulnerability was fixed in Firefox for iOS 143.1.

Risk And Classification

Primary CVSS: v3.1 4 MEDIUM from ADP

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

EPSS: 0.000160000 probability, percentile 0.034790000 (date 2026-04-15)

Problem Types: CWE-359 | CWE-359 CWE-359 Exposure of Private Personal Information to an Unauthorized Actor

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED4MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary4MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v3.1 Breakdown

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

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Mozilla Firefox All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mozilla Firefox For IOS unaffected 143.1 * rpm Not specified

References

ReferenceSourceLinkTags
www.mozilla.org/security/advisories/mfsa2025-79 [email protected] www.mozilla.org Vendor Advisory
bugzilla.mozilla.org/show_bug.cgi [email protected] bugzilla.mozilla.org Issue Tracking, 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: Muneaki Nishimura (en)

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