GLSA 200603-07: flex: Potential insecure code generation

http://security.gentoo.org/

Severity:	normal
Title:	flex: Potential insecure code generation
Date:	03/10/2006
Bugs:	#122940
ID:	200603-07

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	Architecture(s)
sys-devel/flex	< 2.5.33-r1	>= 2.5.33-r1	All supported architectures

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

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@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.