How severe is CVE-2025-10859?

CVE-2025-10859 has a CVSS 3.x base score of 4.0, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2025-10859 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-10859?

CVE-2025-10859 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-10859?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-10859 have an EU (EUVD) identifier?

Yes. CVE-2025-10859 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-31731.

When was CVE-2025-10859 published?

CVE-2025-10859 was published on 2025-09-30 and last updated on 2026-06-17.

CVE-2025-10859

CVE-2025-10859 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 4.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-359.

Key facts

Severity: Medium (CVSS 3.x base score 4.0)
EPSS exploit prediction: 0% (2nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-31731
Weakness: CWE-359
Affected product: Mozilla Firefox
Published: 2025-09-30
Last modified: 2026-06-17

Description

Cookie 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.

Frequently asked questions

What is CVE-2025-10859?: Cookie 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.
How severe is CVE-2025-10859?: CVE-2025-10859 has a CVSS 3.x base score of 4.0, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2025-10859 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-10859?: CVE-2025-10859 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-10859?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-10859 have an EU (EUVD) identifier?: Yes. CVE-2025-10859 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-31731.
When was CVE-2025-10859 published?: CVE-2025-10859 was published on 2025-09-30 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:iphone_os:*:*

More vulnerabilities in Mozilla Firefox

CVE-2026-4725 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149…
CVE-2026-4692 — Critical (CVSS 10.0): Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Firefox ESR…
CVE-2026-4689 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was…
CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
CVE-2026-2778 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in…
CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…

All CVEs affecting Mozilla Firefox →

Other CWE-359 vulnerabilities

CVE-2022-0482 — Critical (CVSS 9.1): Exposure of Private Personal Information to an Unauthorized Actor in GitHub repository alextselegidis/easyappointments…
CVE-2022-2921 — High (CVSS 8.8): Exposure of Private Personal Information to an Unauthorized Actor in GitHub repository notrinos/notrinoserp prior to…
CVE-2025-53625 — High (CVSS 8.7): The DynamicPageList3 extension is a reporting tool for MediaWiki, listing category members and intersections with…
CVE-2025-13008 — High (CVSS 8.6): An information disclosure vulnerability in M-Files Server before versions 25.12.15491.7, 25.8 LTS SR3, 25.2 LTS SR3 and…
CVE-2023-36052 — High (CVSS 8.6): Azure CLI REST Command Information Disclosure Vulnerability
CVE-2024-26192 — High (CVSS 8.2): Microsoft Edge (Chromium-based) Information Disclosure Vulnerability

Browse all CWE-359 vulnerabilities →