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TI-2015-05507 Aliases CVE-2015-6564GHSA-cm6p-9f8w-c878

Use-after-free vulnerability in the mm_answer_pam_free_ctx function in monitor.c in sshd…

Priority LOW 34CWE-416Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
High
Impact type
Code execution, Security bypass
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 16 fixed, 2 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-416, CWE-264 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00599 48th percentileScored 2026-11-07
Fix Partial Red Hat: 2 advisoriesRed Hat: 16 fixed, 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*up to 6.9VulnerableOpenBSD
  • cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:* Versions up to 6.9 Vulnerable ·OpenBSD

Remediation

Red Hat 2 advisories

  • RHSA-2016:0741 Released 2016-05-10 · Red Hat rating Moderate
    openssh security, bug fix, and enhancement update
    • Red Hat Enterprise Linux Desktop (v. 6) openssh-5.3p1-117.el6, openssh-askpass-5.3p1-117.el6, openssh-clients-5.3p1-117.el6 +1
    • Red Hat Enterprise Linux Desktop Optional (v. 6) openssh-ldap-5.3p1-117.el6, pam_ssh_agent_auth-0.9.3-117.el6
    • Red Hat Enterprise Linux HPC Node (v. 6) openssh-5.3p1-117.el6, openssh-clients-5.3p1-117.el6, openssh-server-5.3p1-117.el6
    • Red Hat Enterprise Linux HPC Node Optional (v. 6) openssh-askpass-5.3p1-117.el6, openssh-ldap-5.3p1-117.el6, pam_ssh_agent_auth-0.9.3-117.el6
    • Red Hat Enterprise Linux Server (v. 6) openssh-5.3p1-117.el6, openssh-askpass-5.3p1-117.el6, openssh-clients-5.3p1-117.el6 +1
    • Red Hat Enterprise Linux Server Optional (v. 6) openssh-ldap-5.3p1-117.el6, pam_ssh_agent_auth-0.9.3-117.el6, pam_ssh_agent_auth-0.9.3-117.el6.ppc
    • Red Hat Enterprise Linux Workstation (v. 6) openssh-5.3p1-117.el6, openssh-askpass-5.3p1-117.el6, openssh-clients-5.3p1-117.el6 +1
    • Red Hat Enterprise Linux Workstation Optional (v. 6) openssh-ldap-5.3p1-117.el6, pam_ssh_agent_auth-0.9.3-117.el6
  • RHSA-2015:2088 Released 2015-11-19 · Red Hat rating Moderate
    openssh security, bug fix, and enhancement update
    • Red Hat Enterprise Linux Client (v. 7) openssh-6.6.1p1-22.el7, openssh-askpass-6.6.1p1-22.el7, openssh-clients-6.6.1p1-22.el7 +2
    • Red Hat Enterprise Linux Client Optional (v. 7) openssh-ldap-6.6.1p1-22.el7, openssh-server-sysvinit-6.6.1p1-22.el7, pam_ssh_agent_auth-0.9.3-9.22.el7
    • Red Hat Enterprise Linux ComputeNode (v. 7) openssh-6.6.1p1-22.el7, openssh-clients-6.6.1p1-22.el7, openssh-keycat-6.6.1p1-22.el7 +1
    • Red Hat Enterprise Linux ComputeNode Optional (v. 7) openssh-askpass-6.6.1p1-22.el7, openssh-ldap-6.6.1p1-22.el7, openssh-server-sysvinit-6.6.1p1-22.el7 +1
    • Red Hat Enterprise Linux Server (v. 7) openssh-6.6.1p1-22.el7, openssh-askpass-6.6.1p1-22.el7, openssh-clients-6.6.1p1-22.el7 +2
    • Red Hat Enterprise Linux Server Optional (v. 7) openssh-askpass-6.6.1p1-22.el7, openssh-ldap-6.6.1p1-22.el7, openssh-server-sysvinit-6.6.1p1-22.el7 +2
    • Red Hat Enterprise Linux Workstation (v. 7) openssh-6.6.1p1-22.el7, openssh-askpass-6.6.1p1-22.el7, openssh-clients-6.6.1p1-22.el7 +2
    • Red Hat Enterprise Linux Workstation Optional (v. 7) openssh-ldap-6.6.1p1-22.el7, openssh-server-sysvinit-6.6.1p1-22.el7, pam_ssh_agent_auth-0.9.3-9.22.el7

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 4AffectedNo fix planned: Will not fix
Red Hat Enterprise Linux 5AffectedNo fix planned: Will not fix
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2015:2088
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2015:2088
Red Hat Enterprise Linux ComputeNode (v. 7)Fixed RHSA-2015:2088
Red Hat Enterprise Linux ComputeNode Optional (v. 7)Fixed RHSA-2015:2088
Red Hat Enterprise Linux Desktop (v. 6)Fixed RHSA-2016:0741
Red Hat Enterprise Linux Desktop Optional (v. 6)Fixed RHSA-2016:0741
Red Hat Enterprise Linux HPC Node (v. 6)Fixed RHSA-2016:0741
Red Hat Enterprise Linux HPC Node Optional (v. 6)Fixed RHSA-2016:0741
Red Hat Enterprise Linux Server (v. 6)Fixed RHSA-2016:0741
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2015:2088
Red Hat Enterprise Linux Server Optional (v. 6)Fixed RHSA-2016:0741
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2015:2088
Red Hat Enterprise Linux Workstation (v. 6)Fixed RHSA-2016:0741
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2015:2088
Red Hat Enterprise Linux Workstation Optional (v. 6)Fixed RHSA-2016:0741
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2015:2088

Timeline

  1. 2026-10-02 Threatist record created from CVE-2015-6564
  2. 2026-10-03 Alias added: GHSA-cm6p-9f8w-c878

References

Advisory 5

Other 10

  • TI-2023-19792 The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently… CVSS 3.1CRITICAL 9.8
  • TI-2024-05929 Openssh: regresshion - race condition in ssh allows rce/dos CVSS 3.1HIGH 8.1
  • TI-2023-10601 OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during… CVSS 3.1MEDIUM 6.5
  • TI-2018-11033 OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying… CVSS 3.1MEDIUM 5.9
  • TI-2016-08105 Untrusted search path vulnerability in ssh-agent.c in ssh-agent in OpenSSH before 7.4… CVSS 3.1HIGH 7.3
  • TI-2023-28040 In ssh in OpenSSH before 9.6, OS command injection might occur if a user name or host… CVSS 3.1MEDIUM 6.5
See all 145 →

Sources

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