Bug 1789069 (CVE-2019-11044) - CVE-2019-11044 php: link function accepts filenames with embedded null byte and treats them as terminating at that byte on Windows
Summary: CVE-2019-11044 php: link function accepts filenames with embedded null byte a...
Alias: CVE-2019-11044
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On:
Blocks: 1789070
TreeView+ depends on / blocked
Reported: 2020-01-08 16:46 UTC by Guilherme de Almeida Suckevicz
Modified: 2021-02-16 20:48 UTC (History)
5 users (show)

Fixed In Version: php 7.3.14RC1
Doc Type: If docs needed, set a value
Doc Text:
A flaw was discovered in the link function in PHP. When compiled on Windows, it does not correctly handle paths containing NULL bytes. An attacker could abuse this flaw to bypass application checks on file paths.
Clone Of:
Last Closed: 2020-01-15 14:09:26 UTC

Attachments (Terms of Use)

Description Guilherme de Almeida Suckevicz 2020-01-08 16:46:30 UTC
In PHP versions 7.2.x below 7.2.26, 7.3.x below 7.3.13 and 7.4.0 on Windows, PHP link() function accepts filenames with embedded \0 byte and treats them as terminating at that byte. This could lead to security vulnerabilities, e.g. in applications checking paths that the code is allowed to access.


Comment 1 Riccardo Schirone 2020-01-15 08:57:16 UTC
Upstream fix:

Comment 2 Riccardo Schirone 2020-01-15 10:43:39 UTC
This flaw is present in the file ext/standard/link_win32.c, which is compiled only on Windows builds.

Similar code is present in ext/standard/link.c and there was a similar flaw there in the past, named CVE-2006-7243. This was however fixed in the versions of php we ship.

Comment 3 Riccardo Schirone 2020-01-15 10:47:02 UTC

This issue did not affect the versions of php as shipped with Red Hat Enterprise Linux 5, 6, 7, and 8 as the flaw only affects Windows builds. See CVE-2006-7243 for the Linux version of this flaw.

Comment 4 Product Security DevOps Team 2020-01-15 14:09:26 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


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