flex: Potential insecure code generation

Background

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

Description

A heap-based buffer overflow in the yy_get_next_buffer function in Flex might allow context-dependent attackers to cause a denial of service or possibly execute arbitrary code via vectors involving num_to_read.

Impact

Context-dependent attackers could cause a Denial of Service condition or possibly execute arbitrary code with the privileges of the process.

Workaround

There is no known workaround at this time.

Resolution

All flex users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=sys-devel/flex-2.6.1"

Packages which depend on flex may need to be recompiled. Tools such as qdepends (included in app-portage/portage-utils) may assist in identifying these packages:

 # emerge --oneshot --ask --verbose $(qdepends -CQ sys-devel/flex | sed
 's/^/=/')