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A use-after-free vulnerability exists in the WebRTC Signaling component of affected Mozilla products. This memory corruption flaw, classified as CWE-416, occurs when the program continues to use a pointer to a memory location after it has been freed. In the context of WebRTC signaling, this error can be triggered during the negotiation of real-time communication sessions, such as video calls, within the browser. The improper management of memory objects during session setup or teardown sequences leaves a dangling pointer. A remote attacker can exploit this condition by crafting a malicious website designed to trigger specific, flawed WebRTC operations. When a victim visits this site, the malicious code manipulates the freed memory block, which may have been reallocated for other data. By controlling the contents of this memory, the attacker can corrupt the browser’s process memory. Successful exploitation leads to arbitrary code execution within the context of the browser, potentially allowing full system compromise. The attack requires no user interaction beyond loading a page and no special privileges, making it highly severe.
DailyCVE Form
Platform: Mozilla Firefox Thunderbird
Version: < 146.0
Vulnerability: Use-after-free
Severity: Critical
Date: 2025-12-09
Prediction: Patched 2025-12-09
What Undercode Say:
Analytics:
Check Firefox version on Linux firefox --version | grep -oP '[0-9]+.[0-9.]+' Check installed Thunderbird version (RHEL-based systems) rpm -q thunderbird Download and verify fixed Firefox ESR package for RHEL 9 wget [bash]/firefox-140.6.0-1.el9_7.x86_64.rpm rpm -K firefox-140.6.0-1.el9_7.x86_64.rpm
How Exploit:
Attackers host malicious websites containing crafted JavaScript designed to manipulate WebRTC session objects. The exploit triggers the use-after-free condition during the signaling process, corrupting memory to gain control over the instruction pointer. This technique falls under the “Drive-by Compromise” tactic (TA0001, T1189). No known public exploits exist as of the publication date.
Protection from this CVE:
Update to Firefox 146, Firefox ESR 140.6, Thunderbird 146, or Thunderbird ESR 140.6 immediately. For enterprise systems, apply vendor-provided security updates; Red Hat has released advisories RHSA-2025:23034 and RHSA-2025:23035 containing the patched packages. Organizations should enforce network-based URL filtering and keep browsers restricted to latest vendor-supported versions.
Impact:
High impact. Successful exploitation allows arbitrary code execution on the target system. An attacker can install programs, view/change/delete data, and create new accounts with full rights. The CVSS 3.1 base score is 9.8 (Critical: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
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Sources:
Reported By: nvd.nist.gov
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