Security researchers have discovered a vulnerability, designated as CVE-2023-29536, which exists in multiple Mozilla products. This critical security flaw might allow an attacker to manipulate memory management within the affected system, causing memory corruption, assertions, and potentially exploitable crashes. Affected products include Mozilla Firefox, Focus for Android, Firefox ESR, Firefox for Android, and Thunderbird.

The CVE-2023-29536 vulnerability arises when an attacker can cause the memory manager of Mozilla-based applications to incorrectly free a pointer that addresses attacker-controlled memory. As a result, they may crash the system or, worse, allow an exploiter to execute arbitrary code on the victim’s device. The vulnerability affects versions of Firefox prior to 112, Focus for Android prior to 112, Firefox ESR prior to 102.10, Firefox for Android prior to 112, and Thunderbird prior to 102.10.

Code Snippet

An example of a vulnerable code snippet that may trigger the CVE-2023-29536 memory management flaw looks like this:


void vulnerable_function() {
    int *pointer = NULL;

    if(some_condition) {
        pointer = (int*) attacker_controlled_malloc(1024);
    } else {
        pointer = (int*) safe_malloc(1024);

    // ...
    // Rest of the function
    // ...

    free(pointer); // Erroneous free() call causing incorrect pointer usage

Exploit Details

The vulnerability potentially allows an attacker to construct and send a specifically crafted payload to the affected application, causing the memory manager to release or "free" a pointer which still points to attacker-controlled memory. This may lead to memory corruption or even enable the attacker to execute arbitrary code on the victim's machine. In some cases, it might also cause assertion failures, which could crash the application.

Fix and Mitigation

Mozilla has already released patches for the affected products, and users are advised to update to the latest versions immediately:

Thunderbird: Update to version 102.10 or higher

To mitigate further risks, users should be cautious when opening email attachments, clicking on links, or visiting unfamiliar websites.

You can find additional information on the CVE-2023-29536 vulnerability from the following sources

1. Mozilla Foundation Security Advisory (MFSA) regarding the CVE-2023-29536 vulnerability:
2. CVE Details page for CVE-2023-29536:
3. National Vulnerability Database (NVD) entry for CVE-2023-29536:


Memory management flaws, like the CVE-2023-29536 vulnerability, can be exploited by attackers to gain unauthorized control over a victim's device. It is crucial to keep software updated with the latest security patches to protect against such threats. Stay informed and vigilant for more updates on this vulnerability and any future security advisories.


Published on: 06/02/2023 17:15:00 UTC
Last modified on: 06/09/2023 03:57:00 UTC