A recent vulnerability has been identified in Firefox, specifically in the way it handles allocation checks in Angle for glsl shaders. This issue, registered as CVE-2023-4582, could lead to a buffer overflow when allocating excessive amounts of private shader memory on macOS operating systems. It's important to note that this bug affects only Firefox installations on macOS, with other operating systems being unaffected. The vulnerability impacts Firefox versions earlier than 117, Firefox ESR versions earlier than 115.2, and Thunderbird versions earlier than 115.2.

Exploit Details

The vulnerability stems from the allocation checks in Angle being too lenient for glsl shaders on macOS. As a result, a buffer overflow can occur when allocating an excessive amount of private shader memory. Buffer overflow vulnerabilities can potentially lead to arbitrary code execution or cause the application to crash.

Here is a code snippet that demonstrates an example of the issue

// Vulnerable Angle code in glsl shaders
void AllocateLargePrivateShaderMemory() {
    // ... other code ...
    size_t largeAllocation = xFFFFFF; // Too large allocation size for macOS
    uint8_t *buffer = new uint8_t[largeAllocation]; // Unsafe allocation
    // ... other code ...

The above snippet shows an allocation of a large amount of memory which may result in a buffer overflow on macOS. The issue is due to the allocation check not properly verifying the safety of the memory size being allocated.

Original References

Mozilla Foundation has acknowledged this vulnerability and provided official information and mitigation steps. You can find detailed information on this issue in the following links:
- Mozilla Foundation Security Advisory 2023-03
- CVE-2023-4582 - NVD

Mitigation and Recommendations

To mitigate this vulnerability, users should update their Firefox installations on macOS to the latest version available (Firefox 117, Firefox ESR 115.2, or Thunderbird 115.2). You can follow these steps to update your browser:

Click on "About Firefox."

5. The "About Firefox" window will open, and your browser will automatically check for updates. If available, click on "Restart to Update Firefox."

After updating your browser, the vulnerability should be mitigated, and your system will no longer be at risk for this specific buffer overflow issue. It's essential to keep your software updated to stay protected from security vulnerabilities.

In conclusion, CVE-2023-4582 is a buffer overflow vulnerability due to improperly checking large allocation sizes in Angle for glsl shaders in Firefox on macOS systems. By updating your browser to the latest version, you can effectively address and mitigate this issue. Remember, always keep an eye out for software updates to ensure your system remains secure.


Published on: 09/11/2023 09:15:00 UTC
Last modified on: 09/14/2023 03:52:00 UTC