flex: Potential insecure code generation

Advisory Content :

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Gentoo Linux Security Advisory GLSA 200603-07
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http://security.gentoo.org/
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Severity: Normal
Title: flex: Potential insecure code generation
Date: March 10, 2006
Bugs: #122940
ID: 200603-07

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Synopsis
========

flex might generate code with a buffer overflow, making applications
using such scanners vulnerable to the execution of arbitrary code.

Background
==========

flex is a programming tool used to generate scanners (programs which
recognize lexical patterns in text).

Affected packages
=================

-------------------------------------------------------------------
Package / Vulnerable / Unaffected
-------------------------------------------------------------------
1 sys-devel/flex < 2.5.33-r1 >= 2.5.33-r1

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

Chris Moore discovered a buffer overflow in a special class of
lexicographical scanners generated by flex. Only scanners generated by
grammars which use either REJECT, or rules with a "variable trailing
context" might be at risk.

Impact
======

An attacker could feed malicious input to an application making use of
an affected scanner and trigger the buffer overflow, potentially
resulting in the execution of arbitrary code.

Workaround
==========

Avoid using vulnerable grammar in your flex scanners.

Resolution
==========

All flex users should upgrade to the latest version:

# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-devel/flex-2.5.33-r1"

References
==========

[ 1 ] CVE-2006-0459
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-0459

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

http://security.gentoo.org/glsa/glsa-200603-07.xml

Concerns?
=========

Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users machines is of utmost
importance to us. Any security concerns should be addressed to
security (at) gentoo (dot) org [email concealed] or alternatively, you may
file a bug at
http://bugs.gentoo.org.

License
=======

Copyright 2006 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/2.0

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flex: Potential insecure code generation