The bufprint routine used by capi_cmsg2str does an unbounded vsprintf into a 8192 byte buffer, perhaps hoping it's big enough. If the content of that vsprintf can be controlled by remote peers, this may lead to a remote security hole for daemons using CAPI (pppd-capi-plugin, asterisk-chan-capi, capi4hylafax, ...). Or a DoS. If the content of that vsprintf can be controlled by local users making use of a system service (such as sending a fax, making a phone call, ...) that uses CAPI, this is a privilege escalation or remote authenticated user security hole, or a DoS.
Created attachment 158099 [details] Patch by Don Howard Upstream patch breaks kABI. The following patch do bounds checking when printing.
A patch addressing this issue has been included in build 2.6.9-55.0.3.EL.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2007-0774.html
*** Bug 402781 has been marked as a duplicate of this bug. ***
*** Bug 402791 has been marked as a duplicate of this bug. ***