RHSA-2019:1488: Important: kernel security and bug fix update
First published: Mon Jun 17 2019(Updated: )
The kernel packages contain the Linux kernel, the core of any Linux operating system.<br>Security Fix(es):<br><li> An integer overflow flaw was found in the way the Linux kernel's networking subsystem processed TCP Selective Acknowledgment (SACK) segments. While processing SACK segments, the Linux kernel's socket buffer (SKB) data structure becomes fragmented. Each fragment is about TCP maximum segment size (MSS) bytes. To efficiently process SACK blocks, the Linux kernel merges multiple fragmented SKBs into one, potentially overflowing the variable holding the number of segments. A remote attacker could use this flaw to crash the Linux kernel by sending a crafted sequence of SACK segments on a TCP connection with small value of TCP MSS, resulting in a denial of service (DoS). (CVE-2019-11477)</li> <li> kernel: Double free in lib/idr.c (CVE-2019-3896)</li> <li> Kernel: tcp: excessive resource consumption while processing SACK blocks allows remote denial of service (CVE-2019-11478)</li> <li> Kernel: tcp: excessive resource consumption for TCP connections with low MSS allows remote denial of service (CVE-2019-11479)</li> For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.<br>Bug Fix(es):<br><li> MDS mitigations not enabled on Intel Skylake CPUs (BZ#1710081)</li> <li> RHEL6 kernel does not disable SMT with mds=full,nosmt (BZ#1710121)</li> <li> [RHEL6] md_clear flag missing from /proc/cpuinfo (BZ#1710517)</li>
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/kernel | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-abi-whitelists | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debug | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debug-debuginfo | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debug-debuginfo | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debug-devel | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debug-devel | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debuginfo | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debuginfo | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debuginfo-common-i686 | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-devel | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-doc | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-firmware | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-headers | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/perf | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/perf-debuginfo | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/perf-debuginfo | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/python-perf | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/python-perf-debuginfo | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/python-perf-debuginfo | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debug | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-devel | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-headers | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/perf | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/python-perf | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debuginfo-common-s390x | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-kdump | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-kdump-debuginfo | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-kdump-devel | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-bootwrapper | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
| redhat/kernel-debuginfo-common-ppc64 | <2.6.32-754.15.3.el6 | 2.6.32-754.15.3.el6 |
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Reference Links
Frequently Asked Questions
What is the severity of RHSA-2019:1488?
The severity of RHSA-2019:1488 is categorized as important due to the potential for exploitation through the kernel's networking subsystem.
How do I fix RHSA-2019:1488?
To fix RHSA-2019:1488, update the kernel package to version 2.6.32-754.15.3.el6 or later.
What is the impact of RHSA-2019:1488?
The impact of RHSA-2019:1488 includes potential privilege escalation due to an integer overflow flaw in TCP SACK segment processing.
Which systems are affected by RHSA-2019:1488?
RHSA-2019:1488 affects Red Hat Enterprise Linux 6 systems utilizing outdated kernel packages.
Is there a specific package I need to upgrade for RHSA-2019:1488?
Yes, you need to upgrade the 'kernel' package to version 2.6.32-754.15.3.el6 or later to remediate RHSA-2019:1488.
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