How severe is CVE-2015-6564?

CVE-2015-6564 has a CVSS 3.x base score of 7.0, rated high severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2015-6564 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-6564?

CVE-2015-6564 affects Openbsd Openssh. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2015-6564?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2015-6564 published?

CVE-2015-6564 was published on 2015-08-24 and last updated on 2026-06-17.

CVE-2015-6564

CVE-2015-6564 is a high-severity vulnerability in Openbsd Openssh with a CVSS 3.x base score of 7.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-264.

Key facts

Severity: High (CVSS 3.x base score 7.0)
CVSS v2: 6.9
EPSS exploit prediction: 1% (44th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-264
Affected product: Openbsd Openssh
Published: 2015-08-24
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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 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.
How severe is CVE-2015-6564?: CVE-2015-6564 has a CVSS 3.x base score of 7.0, rated high severity. It is exploitable over local access with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2015-6564 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (44th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-6564?: CVE-2015-6564 affects Openbsd Openssh. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2015-6564?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2015-6564 published?: CVE-2015-6564 was published on 2015-08-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*

More vulnerabilities in Openbsd Openssh

CVE-2003-0786 — Critical (CVSS 10.0): The SSH1 PAM challenge response authentication in OpenSSH 3.7.1 and 3.7.1p1, when Privilege Separation is disabled,…
CVE-2003-0693 — Critical (CVSS 10.0): A "buffer management error" in buffer_append_space of buffer.c for OpenSSH before 3.7 may allow remote attackers to…
CVE-2002-0640 — Critical (CVSS 10.0): Buffer overflow in sshd in OpenSSH 2.3.1 through 3.3 may allow remote attackers to execute arbitrary code via a large…
CVE-2001-0144 — Critical (CVSS 10.0): CORE SDI SSH1 CRC-32 compensation attack detector allows remote attackers to execute arbitrary commands on an SSH…
CVE-2000-0999 — Critical (CVSS 10.0): Format string vulnerabilities in OpenBSD ssh program (and possibly other BSD-based operating systems) allow attackers…
CVE-2000-0525 — Critical (CVSS 10.0): OpenSSH does not properly drop privileges when the UseLogin option is enabled, which allows local users to execute…

All CVEs affecting Openbsd Openssh →

Other CWE-264 (Permissions, Privileges, and Access Controls) vulnerabilities

CVE-2016-8363 — Critical (CVSS 10.0): An issue was discovered in Moxa OnCell OnCellG3470A-LTE, AWK-1131A/3131A/4131A Series, AWK-3191 Series, AWK-5232/6232…
CVE-2016-7457 — Critical (CVSS 10.0): VMware vRealize Operations (aka vROps) 6.x before 6.4.0 allows remote authenticated users to gain privileges, or halt…
CVE-2015-7425 — Critical (CVSS 10.0): The Data Protection component in the VMware vSphere GUI in IBM Tivoli Storage Manager for Virtual Environments: Data…
CVE-2015-8267 — Critical (CVSS 10.0): The PasswordReset.Controllers.ResetController.ChangePasswordIndex method in PasswordReset.dll in Dovestones AD Self…
CVE-2015-7919 — Critical (CVSS 10.0): SearchBlox 8.3 before 8.3.1 allows remote attackers to write to the config file, and consequently cause a denial of…
CVE-2015-7071 — Critical (CVSS 10.0): The File Bookmark component in Apple OS X before 10.11.2 allows attackers to bypass a sandbox protection mechanism for…

Browse all CWE-264 (Permissions, Privileges, and Access Controls) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

122.114.69.235 (ipv4-addr)
92.47.46.174 (ipv4-addr)
76.12.128.249 (ipv4-addr)
64.53.7.231 (ipv4-addr)
62.182.118.138 (ipv4-addr)
61.76.136.25 (ipv4-addr)
213.135.175.76 (ipv4-addr)
187.237.47.214 (ipv4-addr)