[ASA-201905-16] curl: arbitrary code execution

[Remi Gacogne]

Arch Linux Security Advisory ASA-201905-16
==========================================

Severity: High
Date    : 2019-05-31
CVE-ID  : CVE-2019-5436
Package : curl
Type    : arbitrary code execution
Remote  : Yes
Link    : https://security.archlinux.org/AVG-964

Summary
=======

The package curl before version 7.65.0-1 is vulnerable to arbitrary
code execution.

Resolution
==========

Upgrade to 7.65.0-1.

# pacman -Syu "curl>=7.65.0-1"

The problem has been fixed upstream in version 7.65.0.

Workaround
==========

None.

Description
===========

libcurl before 7.65.0 contains a heap buffer overflow in the function
(tftp_receive_packet()) that receives data from a TFTP server. It calls
recvfrom() with the default size for the buffer rather than with the
size that was used to allocate it. Thus, the content that might
overwrite the heap memory is entirely controlled by the server.

The flaw exists if the user selects to use a "blksize" of 504 or
smaller (default is 512). The smaller size that is used, the larger the
possible overflow becomes. Users choosing a smaller size than default
should be rare as the primary use case for changing the size is to make
it larger.

Impact
======

A malicious TFTP server can execute arbitrary code on the affected
host.

References
==========

https://curl.haxx.se/docs/CVE-2019-5436.html
https://github.com/curl/curl/commit/2576003415625d7b5f0e390902f8097830b82275
https://security.archlinux.org/CVE-2019-5436

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