Bug 1374701 (CVE-2016-7127) - CVE-2016-7127 php: imagegammacorrect allows arbitrary write access
Summary: CVE-2016-7127 php: imagegammacorrect allows arbitrary write access
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2016-7127
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks: 1374715
TreeView+ depends on / blocked
 
Reported: 2016-09-09 13:01 UTC by Martin Prpič
Modified: 2019-12-16 06:42 UTC (History)
14 users (show)

Fixed In Version: php 5.6.25, php 7.0.10
Doc Type: If docs needed, set a value
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Clone Of:
Environment:
Last Closed: 2016-10-20 05:35:38 UTC


Attachments (Terms of Use)


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System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2016:2750 0 normal SHIPPED_LIVE Moderate: rh-php56 security, bug fix, and enhancement update 2016-11-15 16:40:02 UTC

Description Martin Prpič 2016-09-09 13:01:27 UTC
The following flaw was found in PHP:

imagegammacorrect accepts two gamma values, if they don't have the same sign then the palette colors will be assigned values bigger than 0xFF, later this values are used to calculate the transparent color using the gdTrueColorAlpha macro, and a negative value will be assigned to the transparent color. 

A remote attacker could use this flaw to crash a PHP application.

Upstream bug:

https://bugs.php.net/bug.php?id=72730

Upstream patch:

https://github.com/php/php-src/commit/1bd103df00f49cf4d4ade2cfe3f456ac058a4eae?w=1

Comment 1 Huzaifa S. Sidhpurwala 2016-10-20 05:30:00 UTC
Analysis:

In order to exploit this, you need to pass specially crafted values to imagegammacorrect() function, which works on the previously created image object. This implies that the attacker needs to have control over the gamma values being passed to the image, which is an unlikely situation in a normal PHP application.

Comment 2 errata-xmlrpc 2016-11-15 11:45:18 UTC
This issue has been addressed in the following products:

  Red Hat Software Collections for Red Hat Enterprise Linux 6
  Red Hat Software Collections for Red Hat Enterprise Linux 6.7 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7
  Red Hat Software Collections for Red Hat Enterprise Linux 7.2 EUS
  Red Hat Software Collections for Red Hat Enterprise Linux 7.3 EUS

Via RHSA-2016:2750 https://rhn.redhat.com/errata/RHSA-2016-2750.html


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