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zlib: Buffer overflow


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200507-05 / zlib
Release Date July 06, 2005
Latest Revision July 06, 2005: 01
Impact high
Exploitable remote
Package Vulnerable versions Unaffected versions Architecture(s)
sys-libs/zlib < 1.2.2-r1 >= 1.2.2-r1 All supported architectures

Related bugreports: #98121


A buffer overflow has been discovered in zlib, potentially resulting in the execution of arbitrary code.

2.  Impact Information


zlib is a widely used free and patent unencumbered data compression library.


Tavis Ormandy of the Gentoo Linux Security Audit Team discovered a buffer overflow in zlib. A bounds checking operation failed to take invalid data into account, allowing a specifically malformed deflate data stream to overrun a buffer.


An attacker could construct a malformed data stream, embedding it within network communication or an application file format, potentially resulting in the execution of arbitrary code when decoded by the application using the zlib library.

3.  Resolution Information


There is no known workaround at this time.


All zlib users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-libs/zlib-1.2.2-r1"

4.  References


Page updated July 06, 2005

Summary: This is a Gentoo Linux Security Advisory

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