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redhatRedHatRHSA-2019:1602
HistoryJun 25, 2019 - 4:27 p.m.

(RHSA-2019:1602) Important: kernel-alt security update

2019-06-2516:27:31
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171

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

7.8 High

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:N/AC:L/Au:N/C:N/I:N/A:C

0.974 High

EPSS

Percentile

99.9%

The kernel-alt packages provide the Linux kernel version 4.x.

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: 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.

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

7.8 High

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:N/AC:L/Au:N/C:N/I:N/A:C

0.974 High

EPSS

Percentile

99.9%