Rapid7 Vulnerability & Exploit Database

CESA-2005:584: zlib security update

Free InsightVM Trial No credit card necessary
Watch Demo See how it all works
Back to Search

CESA-2005:584: zlib security update



Updated zlib packages that fix a buffer overflow are now available for Red Hat Enterprise Linux 4. This update has been rated as having important security impact by the Red Hat Security Response Team.

Zlib is a general-purpose lossless data compression library that is used by many different programs. A previous zlib update, RHSA-2005:569 (CAN-2005-2096) fixed a flaw in zlib that could allow a carefully crafted compressed stream to crash an application. While the original patch corrected the reported overflow, Markus Oberhumer discovered additional ways a stream could trigger an overflow. An attacker could create a carefully crafted compressed stream that would cause an application to crash if the stream is opened by a user. As an example, an attacker could create a malicious PNG image file that would cause a Web browser or mail viewer to crash if the image is viewed. The Common Vulnerabilities and Exposures project (cve.mitre.org) assigned the name CAN-2005-1849 to this issue. Note that the versions of zlib shipped with CentOS Linux 2.1 and 3 are not vulnerable to this issue. All users should update to these errata packages that contain a patch from Mark Adler that corrects this issue.


  • centos-upgrade-zlib
  • centos-upgrade-zlib-devel

With Rapid7 live dashboards, I have a clear view of all the assets on my network, which ones can be exploited, and what I need to do in order to reduce the risk in my environment in real-time. No other tool gives us that kind of value and insight.

– Scott Cheney, Manager of Information Security, Sierra View Medical Center