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Fencer Intel
high 8.4

CVE-2016-2856 json

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 be…

published 2016-03-14 10 y ago modified 2026-06-17 4 mo ago also EUVD-2016-3929

cvss
8.4
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits
1
Exploit-DB

Summary

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.

Patch / fix

  • glibc Debian 14, Debian 13, Debian 12 2.21-1

debian advisories DEBIAN-CVE-2016-2856

  • eglibc Ubuntu 14.04 LTS 2.19-0ubuntu6.8

ubuntu advisories UBUNTU-CVE-2016-2856

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Timeline

  1. First public exploit (EDB-41760)
  2. Published

Exploit prediction

1.03% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-41760 Ubuntu < 15.10 - PT Chown Arbitrary PTs Access Via User Namespace Privilege Escalation local, 2016-02-22

CVSS scores

assigned by version score vector
NVD 3.0 8.4 CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C

Classification

Weakness
  • CWE-264 Permissions, Privileges, and Access Controls

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.