Updated tcl packages that fix two security issues and one bug are now available for Red Hat Enterprise Linux 5.
The Red Hat Security Response Team has rated this update as having moderate security impact. Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) associated with each description below.
Tcl (Tool Command Language) provides a powerful platform for creating integration applications that tie together diverse applications, protocols, devices, and frameworks. When paired with the Tk toolkit, Tcl provides a fast and powerful way to create cross-platform GUI applications.
- CVE-2007-4772, CVE-2007-6067
Two denial of service flaws were found in the Tcl regular expression handling engine. If Tcl or an application using Tcl processed a specially-crafted regular expression, it would lead to excessive CPU and memory consumption.
Due to a suboptimal implementation of threading in the current version of the Tcl language interpreter, an attempt to use threads in combination with fork in a Tcl script could cause the script to stop responding. At the moment, it is not possible to rewrite the source code or drop support for threading entirely. Consequent to this, this update provides a version of Tcl without threading support in addition to the standard version with this support. Users who need to use fork in their Tcl scripts and do not require threading can now switch to the version without threading support by using the alternatives command.
All users of Tcl are advised to upgrade to these updated packages, which contain backported patches to correct these issues.