#VU40102 Out-of-bounds write in PHP - CVE-2016-7126

Vulnerability identifier: #VU40102

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-2016-7126

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PHP
Universal components / Libraries / Scripting languages

Vendor: PHP Group

Description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

The imagetruecolortopalette function in ext/gd/gd.c in PHP before 5.6.25 and 7.x before 7.0.10 does not properly validate the number of colors, which allows remote attackers to cause a denial of service (select_colors allocation error and out-of-bounds write) or possibly have unspecified other impact via a large value in the third argument.

Mitigation
Install update from vendor's website.

Vulnerable software versions

PHP: 7.0.0 - 7.0.9

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External links
https://openwall.com/lists/oss-security/2016/09/02/9
https://rhn.redhat.com/errata/RHSA-2016-2750.html
https://www.php.net/ChangeLog-5.php
https://www.php.net/ChangeLog-7.php
https://www.securityfocus.com/bid/92755
https://www.securitytracker.com/id/1036680
https://bugs.php.net/bug.php?id=72697
https://github.com/php/php-src/commit/b6f13a5ef9d6280cf984826a5de012a32c396cd4?w=1
https://security.gentoo.org/glsa/201611-22
https://www.tenable.com/security/tns-2016-19

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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.