#VU56736 Use-after-free in nginx - CVE-2016-0746

Vulnerability identifier: #VU56736

Vulnerability risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2016-0746

CWE-ID: CWE-416

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
nginx
Server applications / Web servers

Vendor: NGINX

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error when processing a crafted DNS response related to CNAME response processing within the resolver in nginx. A remote attacker can send a specially crafted DNS response to the affected server, trigger a use-after-free error and perform a denial of service attack or execute arbitrary code on the system.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

nginx: 0.6.18 - 0.6.1516, 0.7.0 - 0.7.69, 0.8.0 - 0.8.55, 0.9.0 - 0.9.7, 1.0.0 - 1.0.15, 1.1.0 - 1.1.19, 1.2.0 - 1.2.9, 1.3.0 - 1.3.16, 1.4.0 - 1.4.7, 1.5.0 - 1.5.13, 1.6.0 - 1.6.3, 1.7.0 - 1.7.12, 1.8.0, 1.9.0 - 1.9.9

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External links
https://lists.opensuse.org/opensuse-updates/2016-02/msg00042.html
https://mailman.nginx.org/pipermail/nginx/2016-January/049700.html
https://www.debian.org/security/2016/dsa-3473
https://www.securitytracker.com/id/1034869
https://www.ubuntu.com/usn/USN-2892-1
https://access.redhat.com/errata/RHSA-2016:1425
https://bto.bluecoat.com/security-advisory/sa115
https://bugzilla.redhat.com/show_bug.cgi?id=1302588
https://security.gentoo.org/glsa/201606-06

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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.