Riskcovery

CVE-2026-8959

Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component

State
Published
Severity
9.6 Critical
Published
May 19, 2026
Updated
May 19, 2026
Reserved
May 19, 2026

Read the record on cve.org

Description

Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Scores

CVSSScoreVectorSource
3.19.6 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HCISA-ADP

Weaknesses

  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
  • CWE-20 Improper Input Validation
  • CWE-693 Protection Mechanism Failure

Affected Products

ProductVersions
FirefoxMozilla
  • 140.11 through 140.*Not affected
  • 151 and laterNot affected
ThunderbirdMozilla
  • 140.11 through 140.*Not affected
  • 151 and laterNot affected

References

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