CVE-2019-11478

high

Published 2019-06-17 · Modified 2019-06-17

💬 Discuss on Community ✚ Propose mitigation

CVSS v3

—

CVSS v4 NEW

—

not yet in upstream

VIR risk

8.0

Description

Jonathan Looney discovered that the TCP retransmission queue implementation in tcp_fragment in the Linux kernel could be fragmented when handling certain TCP Selective Acknowledgment (SACK) sequences. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commit f070ef2ac66716357066b683fb0baf55f8191a2e.

Predictions

Exploit likelihood

20%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

Mitigation details

Source: Red Hat Errata — Red Hat Inc. · View original ↗ · Open-Errata-API

Description Kernel: tcp: excessive resource consumption while processing SACK blocks allows remote denial of service Red Hat statement Red Hat Product Security is aware of this issue. Updates will be released as they become available. For additional information, please refer to the Red Hat Knowledgebase article: https://access.redhat.com/security/vulnerabilities/tcpsack Red Hat Enterprise Linux 5…

Description

Kernel: tcp: excessive resource consumption while processing SACK blocks allows remote denial of service

Red Hat statement

Red Hat Product Security is aware of this issue. Updates will be released as they become available. For additional information, please refer to the Red Hat Knowledgebase article: https://access.redhat.com/security/vulnerabilities/tcpsack Red Hat Enterprise Linux 5 is now in Maintenance Support 2 Phase of maintenance life cycle. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.

CVSS v3: 5.3 (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)

Errata / fixed releases

Product	Package	Advisory	Released
Red Hat Enterprise Linux 6	`kernel-0:2.6.32-754.15.3.el6`	RHSA-2019:1488	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 6.5 Advanced Update Support	`kernel-0:2.6.32-431.95.3.el6`	RHSA-2019:1490	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 6.6 Advanced Update Support	`kernel-0:2.6.32-504.79.3.el6`	RHSA-2019:1489	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 7	`kernel-rt-0:3.10.0-957.21.3.rt56.935.el7`	RHSA-2019:1486	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 7	`kernel-0:3.10.0-957.21.3.el7`	RHSA-2019:1481	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 7	`kernel-alt-0:4.14.0-115.8.2.el7a`	RHSA-2019:1602	2019-06-25T00:00:00Z
Red Hat Enterprise Linux 7.2 Advanced Update Support	`kernel-0:3.10.0-327.79.2.el7`	RHSA-2019:1485	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 7.2 Telco Extended Update Support	`kernel-0:3.10.0-327.79.2.el7`	RHSA-2019:1485	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 7.2 Update Services for SAP Solutions	`kernel-0:3.10.0-327.79.2.el7`	RHSA-2019:1485	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 7.3 Advanced Update Support	`kernel-0:3.10.0-514.66.2.el7`	RHSA-2019:1484	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 7.3 Telco Extended Update Support	`kernel-0:3.10.0-514.66.2.el7`	RHSA-2019:1484	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 7.3 Update Services for SAP Solutions	`kernel-0:3.10.0-514.66.2.el7`	RHSA-2019:1484	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 7.4 Extended Update Support	`kernel-0:3.10.0-693.50.3.el7`	RHSA-2019:1483	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 7.5 Extended Update Support	`kernel-0:3.10.0-862.34.2.el7`	RHSA-2019:1482	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 8	`kernel-rt-0:4.18.0-80.4.2.rt9.152.el8_0`	RHSA-2019:1480	2019-06-17T00:00:00Z
Red Hat Enterprise Linux 8	`kernel-0:4.18.0-80.4.2.el8_0`	RHSA-2019:1479	2019-06-17T00:00:00Z
Red Hat Enterprise MRG 2	`kernel-rt-1:3.10.0-693.50.3.rt56.644.el6rt`	RHSA-2019:1487	2019-06-17T00:00:00Z
Red Hat Virtualization 4.2 for Red Hat Enterprise Linux 7.6 EUS	`redhat-release-virtualization-host-0:4.2-11.1.el7`	RHSA-2019:1594	2019-06-25T00:00:00Z
Red Hat Virtualization 4.2 for Red Hat Enterprise Linux 7.6 EUS	`redhat-virtualization-host-0:4.2-20190618.0.el7_6`	RHSA-2019:1594	2019-06-25T00:00:00Z
Red Hat Virtualization 4 for Red Hat Enterprise Linux 7	`redhat-release-virtualization-host-0:4.3.4-1.el7ev`	RHSA-2019:1699	2019-07-08T00:00:00Z
Red Hat Virtualization 4 for Red Hat Enterprise Linux 7	`redhat-virtualization-host-0:4.3.4-20190620.3.el7_6`	RHSA-2019:1699	2019-07-08T00:00:00Z

Package state

Product	Package	State
Red Hat Enterprise Linux 5	`kernel`	Out of support scope

Apply commands

bash fix

Apply RHSA-2019:1488 for Red Hat Enterprise Linux 6

yum update -y kernel
# or:
dnf upgrade -y kernel

OS impact

SUSE Affected 1 release

Version	Status	Fixed in
—	Affected	—

Arch Fixed 1 release

Version	Status	Fixed in
—	Fixed	`5.1.11.a-1`

Debian Fixed 5 releases

Version	Status	Fixed in
trixie	Fixed	`4.19.37-4`
sid	Fixed	`4.19.37-4`
forky	Fixed	`4.19.37-4`
bullseye	Fixed	`4.19.37-4`
bookworm	Fixed	`4.19.37-4`

Red Hat Fixed 1 release

Version	Status	Fixed in
8	Fixed	—

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.