CVE-2021-43539 : Exploit Details and Defense Strategies
Learn about CVE-2021-43539 affecting Mozilla Thunderbird, Firefox ESR, and Firefox versions < 91.4.0 and < 95, leading to a potentially exploitable crash. Find mitigation steps and patches.
A vulnerability in Mozilla Thunderbird, Firefox ESR, and Firefox could lead to a potentially exploitable crash.
Understanding CVE-2021-43539
What is CVE-2021-43539?
Failure to record live pointers correctly across wasm instance calls could result in a GC rooting failure, leading to a potential use-after-free vulnerability.
The Impact of CVE-2021-43539
This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95, potentially allowing for a crash that could be exploited.
Technical Details of CVE-2021-43539
Vulnerability Description
The vulnerability arises from not correctly tracking live pointers across wasm instance calls, potentially resulting in a use-after-free situation.
Affected Systems and Versions
- Thunderbird < 91.4.0
- Firefox ESR < 91.4.0
- Firefox < 95
Exploitation Mechanism
The issue occurs when a GC takes place within a call, failing to trace the live pointers.
Mitigation and Prevention
Immediate Steps to Take
- Upgrade Thunderbird, Firefox ESR, and Firefox to versions 91.4.0 and 95 respectively.
- Monitor vendor security advisories for patches.
Long-Term Security Practices
- Regularly update software to the latest versions.
- Implement secure coding practices to prevent such vulnerabilities.
Patching and Updates
Apply security patches provided by Mozilla for Thunderbird, Firefox ESR, and Firefox.