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CVE-2015-8539

Publication date 7 February 2016

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

7.8 · High

Score breakdown

The KEYS subsystem in the Linux kernel before 4.4 allows local users to gain privileges or cause a denial of service (BUG) via crafted keyctl commands that negatively instantiate a key, related to security/keys/encrypted-keys/encrypted.c, security/keys/trusted.c, and security/keys/user_defined.c.

From the Ubuntu Security Team

Dmitry Vyukov discovered that the key management subsystem in the Linux kernel did not properly restrict adding a key that already exists but is negatively instantiated. 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 18.10 cosmic
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Fixed 3.13.0-161.211
linux-aws 18.10 cosmic
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-azure 18.10 cosmic
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
linux-azure-edge 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
linux-euclid 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 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
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
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
Not affected
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
Not affected
14.04 LTS trusty Not in release
linux-kvm 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-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
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
Not affected
18.04 LTS bionic
Not affected
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

seth-arnold

Debian's triage suggested this was introduced by 146aa8b1453bd8f1ff2304ffb71b4ee0eb9acdcc

sbeattie

verified this is an issue with precise's kernel, the second reproducer in the git commit results in a NULL pointer exception

tyhicks

As sbeattie mentioned above, this is present prior to 4.4. I'm setting the break commit to the start of git history which is after user keys were added

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-3798-1
    • Linux kernel vulnerabilities
    • 23 October 2018
    • USN-3798-2
    • Linux kernel (Trusty HWE) vulnerabilities
    • 23 October 2018

Other references