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Red Hat: RHSA-2019-1489-01 Important Security Fix For Kernel

red hat
Calendar Grey June 17, 2019
Dist Redhat Esm H88
Kernel refresh for CentOS provides essential bug repairs; key for maintaining system integrity and protection.
An update for kernel is now available for Red Hat Enterprise Linux 6.6 Advanced Update Support

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.

Summary

The kernel packages contain the Linux kernel, the core of any Linux operating system.
Security Fix(es):
* 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)
* kernel: Double free in lib/idr.c (CVE-2019-3896)
* Kernel: tcp: excessive resource consumption while processing SACK blocks allows remote denial of service (CVE-2019-11478)
* Kernel: tcp: excessive resource consumption for TCP connections with low MSS allows remote denial of service (CVE-2019-11479)
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.
Bug Fix(es):
* MDS mitigations not enabled on Intel Skylake CPUs (BZ#1713026)
* [RHEL6] md_clear flag missing from /proc/cpuinfo (BZ#1713029)
* RHEL6 kernel does not disable SMT with mds=full,nosmt (BZ#1713044)

Topics%20covered

Topics Covered

security advisory denial of service kernel update security impact red hat enterprise linux important security fix

References

https://access.redhat.com/security/cve/CVE-2019-3896 https://access.redhat.com/security/cve/CVE-2019-11477 https://access.redhat.com/security/cve/CVE-2019-11478 https://access.redhat.com/security/cve/CVE-2019-11479 https://access.redhat.com/security/updates/classification/#important https://access.redhat.com/security/vulnerabilities/tcpsack

Package List

Red Hat Enterprise Linux Server AUS (v. 6.6):
Source: kernel-2.6.32-504.79.3.el6.src.rpm
noarch: kernel-abi-whitelists-2.6.32-504.79.3.el6.noarch.rpm kernel-doc-2.6.32-504.79.3.el6.noarch.rpm kernel-firmware-2.6.32-504.79.3.el6.noarch.rpm
x86_64: kernel-2.6.32-504.79.3.el6.x86_64.rpm kernel-debug-2.6.32-504.79.3.el6.x86_64.rpm kernel-debug-debuginfo-2.6.32-504.79.3.el6.x86_64.rpm kernel-debug-devel-2.6.32-504.79.3.el6.x86_64.rpm kernel-debuginfo-2.6.32-504.79.3.el6.x86_64.rpm kernel-debuginfo-common-x86_64-2.6.32-504.79.3.el6.x86_64.rpm kernel-devel-2.6.32-504.79.3.el6.x86_64.rpm kernel-headers-2.6.32-504.79.3.el6.x86_64.rpm perf-2.6.32-504.79.3.el6.x86_64.rpm perf-debuginfo-2.6.32-504.79.3.el6.x86_64.rpm python-perf-debuginfo-2.6.32-504.79.3.el6.x86_64.rpm
Red Hat Enterprise Linux Server Optional AUS (v. 6.6):
x86_64: kernel-debug-debuginfo-2.6.32-504.79.3.el6.x86_64.rpm kernel-debuginfo-2.6.32-504.79.3.el6.x86_64.rpm kernel-debuginfo-common-x86_64-2.6.32-504.79.3.el6.x86_64.rpm perf-debuginfo-2.6.32-504.79.3.el6.x86_64.rpm python-perf-2.6.32-504.79.3.el6.x86_64.rpm python-perf-debuginfo-2.6.32-504.79.3.el6.x86_64.rpm
These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from https://access.redhat.com/security/team/key/


Severity
important
Lowest
Low
Medium
High
Critical

Advisory ID: RHSA-2019:1489-01
Product: Red Hat Enterprise Linux
Advisory URL: https://access.redhat.com/errata/RHSA-2019:1489
Issue date: 2019-06-17

Topic

An update for kernel is now available for Red Hat Enterprise Linux 6.6Advanced Update Support.Red Hat Product Security has rated this update as having a security impactof Important. A Common Vulnerability Scoring System (CVSS) base score,which gives a detailed severity rating, is available for each vulnerabilityfrom the CVE link(s) in the References section.

Topics%20covered

Topics Covered

security advisory denial of service kernel update security impact red hat enterprise linux important security fix

Relevant Releases Architectures

Red Hat Enterprise Linux Server AUS (v. 6.6) - noarch, x86_64

Red Hat Enterprise Linux Server Optional AUS (v. 6.6) - x86_64

Bugs Fixed

1694812 - CVE-2019-3896 kernel: Double free in lib/idr.c

1719123 - CVE-2019-11477 Kernel: tcp: integer overflow while processing SACK blocks allows remote denial of service

1719128 - CVE-2019-11478 Kernel: tcp: excessive resource consumption while processing SACK blocks allows remote denial of service

1719129 - CVE-2019-11479 Kernel: tcp: excessive resource consumption for TCP connections with low MSS allows remote denial of service

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