Public Date:
2012-A-0148, 2012-A-0153
732658: CVE-2011-3188 kernel: net: improve sequence number generation

The MITRE CVE dictionary describes this issue as:

The (1) IPv4 and (2) IPv6 implementations in the Linux kernel before 3.1 use a modified MD4 algorithm to generate sequence numbers and Fragment Identification values, which makes it easier for remote attackers to cause a denial of service (disrupted networking) or hijack network sessions by predicting these values and sending crafted packets.

Find out more about CVE-2011-3188 from the MITRE CVE dictionary dictionary and NIST NVD.


This issue affects the Linux kernel as shipped with Red Hat Enterprise Linux 4, 5, 6, and Red Hat Enterprise MRG. It has been addressed in Red Hat Enterprise Linux 5, 6, and Red Hat Enterprise MRG via,, and Red Hat Enterprise Linux 4 is now in Production 3 of the maintenance life-cycle,, therefore the fix for this issue is not currently planned to be included in the future updates.

CVSS v2 metrics

NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.

Base Score 5.8
Base Metrics AV:N/AC:M/Au:N/C:N/I:P/A:P
Access Vector Network
Access Complexity Medium
Authentication None
Confidentiality Impact None
Integrity Impact Partial
Availability Impact Partial

Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).

Red Hat Security Errata

Platform Errata Release Date
Red Hat Enterprise Virtualization Hypervisor 5 (rhev-hypervisor) RHSA-2011:1408 2011-10-26
MRG Grid for RHEL 6 Server v.2 (kernel-rt) RHSA-2012:0010 2012-01-10
Red Hat Enterprise Linux version 5 (kernel) RHSA-2011:1386 2011-10-20
Red Hat Enterprise Linux EUS (v. 5.6 server) (kernel) RHSA-2011:1419 2011-11-01
Red Hat Enterprise Linux version 6 (kernel) RHSA-2011:1465 2011-11-22

Affected Packages State

Platform Package State
Red Hat Enterprise Linux EUS (v. 5.6 server) kernel Affected
Red Hat Enterprise Linux 4 kernel Will not fix


Red Hat would like to thank Dan Kaminsky for reporting this issue.