Vulnerability identifier: #VU11789

Vulnerability risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-7890

CWE-ID: CWE-200

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PHP
Universal components / Libraries / Scripting languages

Vendor: PHP Group

Description

The vulnerability allows a remote attacker to obtain potentially sensitive information.

The weakness exists in the GIF decoding function gdImageCreateFromGifCtx in gd_gif_in.c due to it does not zero colorMap arrays before use. A remote attacker can trick the victim into opening a specially crafted GIF image that could use the uninitialized tables to read ~700 bytes from the top of the stack and gain access to potentially sensitive information.

Mitigation
Update to versions 5.6.31 or 7.1.7.

Vulnerable software versions

PHP: 5.6.0 - 5.6.30, 7.1.0 - 7.1.6

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External links
http://php.net/ChangeLog-5.php

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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.