Remote code execution in Mozilla Firefox and Firefox ESR

Published: 2023-09-12 | Updated: 2024-06-07
Risk Critical
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2023-5129
Exploitation vector Network
Public exploit Vulnerability #1 is being exploited in the wild.
Vulnerable software
Firefox for Android
Mobile applications / Apps for mobile phones

Firefox for iOS
Mobile applications / Apps for mobile phones

Mozilla Firefox
Client/Desktop applications / Web browsers

Firefox ESR
Client/Desktop applications / Web browsers

Vendor Mozilla

Security Bulletin

This security bulletin contains one critical risk vulnerability.

1) Heap-based buffer overflow

EUVDB-ID: #VU80637

Risk: Critical

CVSSv3.1: 8.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2023-5129,CVE-2023-4863

CWE-ID: CWE-122 - Heap-based Buffer Overflow

Exploit availability: Yes


The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error when processing WebP images within libwebp library. A remote attacker can trick the victim to visit a malicious website, trigger a heap-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system. The vulnerability affects all modern browsers that support WebP image processing.

Note, the vulnerability is being actively exploited in the wild.


Install update from vendor's website.

Vulnerable software versions

Firefox for Android: 66.0.4 - 117.0

Firefox for iOS: 8.0 - 117.0

Mozilla Firefox: 100.0 - 117.0

Firefox ESR: 102.0 - 115.2.0

External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to perform certain actions on the device.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.