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CVE-2018-6559

Publication date 18 October 2018

Last updated 24 July 2024

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

3.3 · Low

Score breakdown

The Linux kernel, as used in Ubuntu 18.04 LTS and Ubuntu 18.10, allows local users to obtain names of files in which they would not normally be able to access via an overlayfs mount inside of a user namespace.

From the Ubuntu Security Team

Philipp Wendler discovered that the overlayfs implementation in the Linux kernel did not properly verify the directory contents permissions from within a unprivileged user namespace. A local attacker could use this to expose sensitive information (protected file names).

Read the notes from the security team

Status

Package Ubuntu Release Status
linux 18.10 cosmic
Fixed 4.18.0-12.13
18.04 LTS bionic
Fixed 4.15.0-42.45
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-aws 18.10 cosmic
Fixed 4.18.0-1006.7
18.04 LTS bionic
Fixed 4.15.0-1029.30
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-aws-hwe 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-azure 18.10 cosmic
Fixed 4.18.0-1006.6
18.04 LTS bionic
Fixed 4.15.0-1035.36
16.04 LTS xenial
Fixed 4.15.0-1035.36~16.04.1
14.04 LTS trusty
Fixed 4.15.0-1035.36~14.04.2
linux-azure-edge 18.10 cosmic Not in release
18.04 LTS bionic
Fixed 4.15.0-1035.36
16.04 LTS xenial
Fixed 4.15.0-1035.36~16.04.1
14.04 LTS trusty Not in release
linux-euclid 18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-flo 18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-gcp 18.10 cosmic
Fixed 4.18.0-1004.5
18.04 LTS bionic
Fixed 4.15.0-1025.26
16.04 LTS xenial
Fixed 4.15.0-1025.26~16.04.1
14.04 LTS trusty Not in release
linux-gcp-edge 18.10 cosmic Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
linux-gke 18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-goldfish 18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-grouper 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 18.10 cosmic Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial
Fixed 4.15.0-42.45~16.04.1
14.04 LTS trusty Not in release
linux-hwe-edge 18.10 cosmic Not in release
18.04 LTS bionic
Not affected
16.04 LTS xenial
Fixed 4.15.0-42.45~16.04.1
14.04 LTS trusty Not in release
linux-kvm 18.10 cosmic
Fixed 4.18.0-1005.5
18.04 LTS bionic
Fixed 4.15.0-1027.27
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-lts-trusty 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 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-vivid 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-wily 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-xenial 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 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 18.10 cosmic Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-manta 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 18.10 cosmic
Fixed 4.15.0-1028.33
18.04 LTS bionic
Fixed 4.15.0-1028.33
16.04 LTS xenial Ignored
14.04 LTS trusty Not in release
linux-oracle 18.10 cosmic
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-raspi2 18.10 cosmic
Fixed 4.18.0-1007.9
18.04 LTS bionic
Fixed 4.15.0-1029.31
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
linux-snapdragon 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

This CVE is specific to Ubuntu since Ubuntu allows overlayfs mounts inside of user namespaces This flaw was previously discovered and fixed as part of CVE-2015-1328. The fix for CVE-2015-1328 was incorrectly dropped from the Ubuntu kernel during a merge with related changes in the upstream Linux kernel. CVE-2018-6559 represents the portion of CVE-2015-1328 that was incorrectly reintroduced into the Ubuntu kernel.

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 3.3 · Low
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality Low
Integrity impact None
Availability impact None
Vector CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

References

Related Ubuntu Security Notices (USN)

    • USN-3835-1
    • Linux kernel vulnerabilities
    • 3 December 2018
    • USN-3833-1
    • Linux kernel (AWS) vulnerabilities
    • 30 November 2018
    • USN-3836-1
    • Linux kernel vulnerabilities
    • 3 December 2018
    • USN-3836-2
    • Linux kernel (HWE) vulnerabilities
    • 4 December 2018
    • USN-3832-1
    • Linux kernel (AWS) vulnerabilities
    • 30 November 2018

Other references