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CVE-2016-2856

Publication date 13 March 2016

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

8.4 · High

Score breakdown

pt_chown in the glibc package before 2.19-18+deb8u4 on Debian jessie; the elibc package before 2.15-0ubuntu10.14 on Ubuntu 12.04 LTS and before 2.19-0ubuntu6.8 on Ubuntu 14.04 LTS; and the glibc package before 2.21-0ubuntu4.2 on Ubuntu 15.10 and before 2.23-0ubuntu1 on Ubuntu 16.04 LTS and 16.10 lacks a namespace check associated with file-descriptor passing, which allows local users to capture keystrokes and spoof data, and possibly gain privileges, via pts read and write operations, related to debian/sysdeps/linux.mk. NOTE: this is not considered a vulnerability in the upstream GNU C Library because the upstream documentation has a clear security recommendation against the --enable-pt_chown option.

From the Ubuntu Security Team

Martin Carpenter discovered that pt_chown in the GNU C Library did not properly check permissions for tty files. A local attacker could use this to gain administrative privileges or expose sensitive information.

Status

Package Ubuntu Release Status
eglibc 17.04 zesty Not in release
16.10 yakkety Not in release
16.04 LTS xenial Not in release
15.10 wily Not in release
14.04 LTS trusty
Fixed 2.19-0ubuntu6.8
12.04 LTS precise
Fixed 2.15-0ubuntu10.14
glibc 17.04 zesty
Not affected
16.10 yakkety
Not affected
16.04 LTS xenial
Not affected
15.10 wily
Fixed 2.21-0ubuntu4.2
14.04 LTS trusty Not in release
12.04 LTS precise Not in release

Patch details

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

Package Patch details
glibc

Severity score breakdown

Parameter Value
Base score 8.4 · High
Attack vector Local
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H