Vulnerability identifier: #VU7831

Vulnerability risk: High

CVSSv3.1: 8.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-7784

CWE-ID: CWE-416

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Mozilla Firefox
Client/Desktop applications / Web browsers

Vendor: Mozilla

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

The weakness exists due to use-after-free error when reading an image observer during frame reconstruction after the observer has been freed. A remote attacker can trick the victim into visiting a specially crafted website, trigger memory corruption and execute arbitrary code with privileges of the current user.

Successful exploitation of the vulnerability may result in system compromise.

Mitigation
Update to version 55.0.

Vulnerable software versions

Mozilla Firefox: 45.0 - 54.0

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2017-18/

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Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.