CVE-2026-16387 (GCVE-0-2026-16387)

Vulnerability from cvelistv5 – Published: 2026-07-21 12:38 – Updated: 2026-07-22 19:18
VLAI
Title
Site isolation issue in the Networking component
Summary
Site isolation issue in the Networking component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
  • CWE-346 - Origin Validation Error
  • CWE-284 - Improper Access Control
  • CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
Assigner
References
Impacted products
Vendor Product Version
Mozilla Firefox Unaffected: 140.13 , ≤ 140.* (rpm)
Unaffected: 153 , ≤ * (rpm)
Create a notification for this product.
Mozilla Thunderbird Unaffected: 140.13 , ≤ 140.* (rpm)
Unaffected: 153 , ≤ * (rpm)
Create a notification for this product.
Credits
Atsushi Sada
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.