As the importance of cybersecurity continues to grow, we must keep an eye on the latest threats and vulnerabilities that could potentially affect the software we use every day. One such vulnerability was recently disclosed, which affects popular web browser Firefox as well as email client Thunderbird. Named CVE-2022-1097, this critical issue is related to the handling of NSSToken objects, and its exploitation could lead to a use-after-free condition and, in some cases, a full-blown system crash.

In this post, we'll take a closer look at this vulnerability, demonstrating how it could be exploited and providing the necessary details for understanding the underlying issue. Furthermore, we'll examine the affected software versions and offer recommendations on how to mitigate the risks associated with CVE-2022-1097.

Overview of CVE-2022-1097

The CVE-2022-1097 vulnerability stems from the direct pointing of NSSToken objects, which could have been accessed unsafely across different threads. This unsafe handling leads to a situation where objects in memory are freed before they should be, resulting in a use-after-free condition that can ultimately cause a crash.

Firefox ESR < 91.8

According to the official CVE entry, this vulnerability has a base score of 8.8, highlighting the critical nature of the issue.

Code Snippet Demonstrating the Vulnerability

Below is a simplified example of the vulnerable code, where NSSToken objects are being accessed directly using pointers, potentially leading to the use-after-free condition:

class NSSToken {
  void ProcessData();

void VulnerableFunction() {
  NSSToken *token = new NSSToken();

  std::thread t1([token]() { token->ProcessData(); });
  std::thread t2([token]() { delete token; }); // Unsafe deletion


In this example, we create an NSSToken object, spawn two threads, and pass the object pointer to both threads. The first thread calls the ProcessData() function on the object, while the second thread deletes it. This concurrent access could lead to the object being deleted before or during its usage in the first thread, causing a use-after-free condition.

Exploit Details

The exploitation of CVE-2022-1097 would involve an attacker crafting a malicious website or email that triggers the vulnerable code. By causing a use-after-free condition in the software, an attacker could potentially execute arbitrary code, crash the system, or cause other negative effects.

For a more detailed technical analysis of the vulnerability and potential exploit techniques, you can refer to the Mozilla Security Advisory discussing the issue.

Mitigation and Recommendations

To protect yourself from this vulnerability, it's crucial to update your software to the latest version. The developers have already patched the issue in the following software versions:

Firefox ESR 91.8

By updating to these versions, you can ensure that you're protected from CVE-2022-1097 and reduce the risks associated with this vulnerability.

In conclusion, CVE-2022-1097 is a critical vulnerability affecting Firefox and Thunderbird, underlining the importance of keeping software up-to-date and maintaining strong cybersecurity practices. By understanding the issue and following recommended mitigation steps, you can prevent potential exploitation and keep your systems secure against this threat.


Published on: 12/22/2022 20:15:00 UTC
Last modified on: 12/29/2022 17:52:00 UTC