CVE-2015-6564: openbsd openssh
Vulnerability summary
CVE-2015-6564 is a high (CVSS 7.0) vulnerability in openbsd openssh. EPSS estimates a 0.60% chance of exploitation in the next 30 days, higher than 48.7% of scored vulnerabilities.
Not severe (CVSS 7, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 6 · Related 4Timeline
- 24-08-2015PublishedVulnerability first disclosed.
- 27-05-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 4 sources · 2 versions- NVDNIST7.0HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated7.0HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.0HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.60%
Chance of exploitation in the next 30 days
Percentile
49%
Versus all other CVEs
30-day change
Decrease -0.01 pp
From 0.60% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-264Permissions, Privileges, and Access ControlsWeaknesses in this category are related to the management of permissions, privileges, and other security features that are used to perform access control.
- CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Affected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian1 product
- openssh< 1:6.9p1-1
Openbsd1 product
- openssh≤ 6.9
Ubuntu1 product
- openssh< 1:6.6p1-2ubuntu2.2
3 vendors · 3 products
References
22 links- www.securityfocus.com/bid/76317VDB Entry
- security.gentoo.org/glsa/201512-04Vendor Advisory
- rhn.redhat.com/errata/RHSA-2016-0741.htmlVendor Advisory
