#VU8616 Use-after-free in Mozilla Firefox - CVE-2017-7793

Vulnerability identifier: #VU8616

Vulnerability risk: High

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2017-7793

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 vulnerability exists due to use-after-free error in the Fetch API when the worker or the associated window are freed when still in use. A remote unauthenticated attacker can create a specially crafted web page, trick the victim into visiting it and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Update to version 56.0.

Vulnerable software versions

Mozilla Firefox: 48.0 - 55.0.3

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External links
https://www.mozilla.org/en-US/security/advisories/mfsa2017-21/

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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.