Is CVE-2015-6563 in the CISA KEV catalog?

No. CVE-2015-6563 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2015-6563?

CVE-2015-6563 has a CVSS v3 base score of 6.4 (MEDIUM).

What is the EPSS score for CVE-2015-6563?

CVE-2015-6563 has an EPSS score of 0.38% (30th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2015-6563?

Upgrade openssh on debian 11 to 1:6.9p1-1 or later.

CVE & CISA-KEV Catalog

CVE-2015-6563

MEDIUM

6.4

CVSS v3

NVD

Description

The monitor component in sshd in OpenSSH before 7.0 on non-OpenBSD platforms accepts extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allows local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c.

CWE-20Improper Input Validation

How to fix

Remediation Available

opensshDebian

Fixed in:1:6.9p1-1CVE-2015-6563

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityHigh

Privileges RequiredHigh

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.38%probability of exploitation in 30 days

30thpercentile

Low risk: more likely to be exploited than 30% of all known CVEs.

References

Vendor Advisory1

openssh.com

Other references17

Related Vulnerabilities

Other CWE-20 (Improper Input Validation) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-3400	Critical	10.0	100%	KEV + Ransom	-
CVE-2021-45105	Medium	5.9	100%	-	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2021-21985	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2018-7600	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-3452	High	7.5	100%	KEV	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-27.