The MITRE CVE dictionary describes this issue as:
The NFSv4 implementation in the Linux kernel before 3.2.2 does not properly handle bitmap sizes in GETACL replies, which allows remote NFS servers to cause a denial of service (OOPS) by sending an excessive number of bitmap words.
Find out more about CVE-2011-4131 from the
MITRE CVE dictionary dictionary and
This issue does not affect the Linux kernel as shipped with Red Hat Enterprise Linux 4 as it does not provide support for NFS ACLs. This issue does not affect the Linux kernel as shipped with Red Hat Enterprise Linux 5. This has been addressed in Red Hat Enterprise MRG via https://rhn.redhat.com/errata/RHSA-2012-0333.html. Future kernel updates in Red Hat Enterprise Linux 6 may address this issue.