CVE-2025-4082

What it actually does

Out-of-bounds read triggered by modification of specific WebGL shader attributes in the rendering engine, enabling information disclosure that can be chained with other vulnerabilities for privilege escalation.

Why it matters to the business

Attackers could gain elevated access on affected macOS systems running the email client, potentially leading to data exposure or further compromise in environments using this software.

How an attack unfolds

An attacker crafts malicious WebGL shader content that modifies specific attributes to trigger an out-of-bounds read; this is then chained with additional vulnerabilities to escalate privileges on macOS Thunderbird instances.

How to fix it

Upgrade Thunderbird to version 138 or 128.10, and ensure any bundled Firefox components are updated to 138, ESR 128.10, or ESR 115.23 on macOS systems.

How to confirm the fix worked

Verify installed versions match or exceed the fixed releases; test WebGL rendering paths with known shader attribute edge cases to confirm absence of out-of-bounds behavior.

Typical attack path

1. Deliver malicious content targeting WebGL shader handling via email or web rendering in Thunderbird on macOS
2. Trigger out-of-bounds read through crafted shader attribute modifications
3. Chain the resulting memory disclosure with other vulnerabilities to achieve privilege escalation

How to detect it

Review application logs and crash reports for unusual WebGL shader errors or memory access violations on macOS; correlate with privilege escalation attempts in system audit logs.

What your security team should do

• Prioritize immediate updates for all macOS Thunderbird deployments to the specified fixed versions
• Audit environments for legacy Thunderbird instances and restrict macOS-specific usage until patched
• Monitor for chained exploitation attempts involving graphics or rendering components