CVE-2019-8912

Publication date 18 February 2019

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

7.8 · High

Score breakdown

In the Linux kernel through 4.20.11, af_alg_release() in crypto/af_alg.c neglects to set a NULL value for a certain structure member, which leads to a use-after-free in sockfs_setattr.

From the Ubuntu Security Team

It was discovered that a use-after-free vulnerability existed in the user- space API for crypto (af_alg) implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Read the notes from the security team

Status

Package Ubuntu Release Status
linux 19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-17.18
18.04 LTS bionic
Fixed 4.15.0-47.50
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-aws 19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-1012.14
18.04 LTS bionic
Fixed 4.15.0-1035.37
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-aws-hwe 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial
Fixed 4.15.0-1035.37~16.04.1
14.04 LTS trusty Not in release
linux-azure 19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-1014.14
18.04 LTS bionic
Fixed 4.18.0-1014.14~18.04.1
16.04 LTS xenial
Fixed 4.15.0-1041.45
14.04 LTS trusty
Fixed 4.15.0-1041.45~14.04.1
linux-azure-edge 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic
Fixed 4.18.0-1014.14~18.04.1
16.04 LTS xenial
Fixed 4.15.0-1041.45
14.04 LTS trusty Not in release
linux-euclid 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-flo 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored abandoned
14.04 LTS trusty Not in release
linux-gcp 19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-1008.9
18.04 LTS bionic
Fixed 4.15.0-1029.31
16.04 LTS xenial
Fixed 4.15.0-1029.31~16.04.1
14.04 LTS trusty Not in release
linux-gcp-edge 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic
Fixed 4.18.0-1008.9~18.04.1
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gke 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Ignored end of standard support
14.04 LTS trusty Not in release
linux-goldfish 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored end of life
14.04 LTS trusty Not in release
linux-grouper 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-hwe 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic
Fixed 4.18.0-17.18~18.04.1
16.04 LTS xenial
Fixed 4.15.0-47.50~16.04.1
14.04 LTS trusty Not in release
linux-hwe-edge 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial
Fixed 4.15.0-47.50~16.04.1
14.04 LTS trusty Not in release
linux-kvm 19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-1009.9
18.04 LTS bionic
Fixed 4.15.0-1031.31
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-lts-trusty 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-lts-utopic 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Ignored end of life, was ignored
linux-lts-vivid 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Ignored end of life, was ignored
linux-lts-wily 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Ignored end of life, was ignored
linux-lts-xenial 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty
Not affected
linux-maguro 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-mako 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored abandoned
14.04 LTS trusty Not in release
linux-manta 19.04 disco Not in release
18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-oem 19.04 disco
Not affected
18.10 cosmic
Fixed 4.15.0-1035.40
18.04 LTS bionic
Fixed 4.15.0-1035.40
16.04 LTS xenial Ignored end of standard support, was needs-triage
14.04 LTS trusty Not in release
linux-oracle 19.04 disco
Not affected
18.10 cosmic
Fixed 4.15.0-1010.12
18.04 LTS bionic
Fixed 4.15.0-1010.12
16.04 LTS xenial
Fixed 4.15.0-1010.12~16.04.1
14.04 LTS trusty Not in release
linux-raspi2 19.04 disco
Not affected
18.10 cosmic
Fixed 4.18.0-1011.13
18.04 LTS bionic
Fixed 4.15.0-1033.35
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-snapdragon 19.04 disco
Not affected
18.10 cosmic Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release

Notes

tyhicks

NVD has published CVSS metrics that state that the attack vector is "Network" which results in a CRITICAL CVSS score but that does not match Ubuntu's assessment. The attack vector is "Local" since AF_ALG is a address family that strictly operates locally between a userspace process and the kernel crypto API and the attack requires a specific sequence of operations to be performed on the file descriptor that represents the socket. This has been addressed in a more generic manner, to fix other network families, by this commit in the net tree: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=ff7b11aa481f682e0e9711abfeb7d03f5cd612bf

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
linux

Severity score breakdown

Parameter Value
Base score 7.8 · High
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-3930-2
    • Linux kernel (HWE) vulnerabilities
    • 2 April 2019
    • USN-3930-1
    • Linux kernel vulnerabilities
    • 2 April 2019
    • USN-3931-2
    • Linux kernel (HWE) vulnerabilities
    • 2 April 2019
    • USN-3931-1
    • Linux kernel vulnerabilities
    • 2 April 2019

Other references