CVE-2026-6759
Description
Use-after-free in the Widget: Cocoa component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Use-after-free in Mozilla Widget:Cocoa component allowing code execution; fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Vulnerability
Overview CVE-2026-6759 is a use-after-free vulnerability in the Widget: Cocoa component of Mozilla Firefox and Thunderbird [1][2][3][4]. This memory safety bug occurs when the program continues to use a pointer after the referenced memory has been freed, potentially leading to exploitable conditions.
Exploitation
Exploitation requires crafted content that triggers the use-after-free. In Thunderbird, scripting is disabled in email, so this flaw cannot be exploited through mail alone [1][3]. However, in browser or browser-like contexts (e.g., Firefox), an attacker could deliver the exploit via a malicious webpage.
Impact
Successful exploitation could allow arbitrary code execution, leading to full system compromise under the user's privileges. The vulnerability is rated High severity with a CVSS v3 score of 7.5.
Mitigation
Mozilla addressed this vulnerability in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10, released on April 21, 2026 [1][2][3][4]. Users are advised to update to these or later versions.
AI Insight generated on May 18, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.
Affected products
4cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*+ 2 more
- cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*range: <150.0
- cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*range: <140.10.0
- (no CPE)range: <150
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*Range: >=140.0,<140.10.0
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
5- www.mozilla.org/security/advisories/mfsa2026-30/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-32/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-33/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-34/nvdVendor Advisory
- bugzilla.mozilla.org/show_bug.cginvdPermissions Required
News mentions
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