How severe is CVE-2016-9566?

CVE-2016-9566 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2016-9566 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-9566?

CVE-2016-9566 affects Nagios. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-9566?

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-2016-9566 published?

CVE-2016-9566 was published on 2016-12-15 and last updated on 2026-06-17.

CVE-2016-9566

CVE-2016-9566 is a high-severity vulnerability in Nagios with a CVSS 3.x base score of 7.8. 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-59.

Key facts

Severity: High (CVSS 3.x base score 7.8)
CVSS v2: 7.2
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-59
Affected product: Nagios
Published: 2016-12-15
Last modified: 2026-06-17

Description

base/logging.c in Nagios Core before 4.2.4 allows local users with access to an account in the nagios group to gain root privileges via a symlink attack on the log file. NOTE: this can be leveraged by remote attackers using CVE-2016-9565.

Frequently asked questions

What is CVE-2016-9566?: base/logging.c in Nagios Core before 4.2.4 allows local users with access to an account in the nagios group to gain root privileges via a symlink attack on the log file. NOTE: this can be leveraged by remote attackers using CVE-2016-9565.
How severe is CVE-2016-9566?: CVE-2016-9566 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2016-9566 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-9566?: CVE-2016-9566 affects Nagios. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-9566?: 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-2016-9566 published?: CVE-2016-9566 was published on 2016-12-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nagios:nagios:*:*:*:*:*:*:*:*

More vulnerabilities in Nagios

CVE-2008-4796 — Critical (CVSS 10.0): The _httpsrequest function (Snoopy/Snoopy.class.php) in Snoopy 1.2.3 and earlier, as used in (1) ampache, (2)…
CVE-2002-1959 — Critical (CVSS 10.0): Nagios 1.0b1 through 1.0b3 allows remote attackers to execute arbitrary commands via shell metacharacters in plugin…
CVE-2016-0726 — Critical (CVSS 9.8): The Fedora Nagios package uses "nagiosadmin" as the default password for the "nagiosadmin" administrator account, which…
CVE-2014-5009 — Critical (CVSS 9.8): Snoopy allows remote attackers to execute arbitrary commands. NOTE: this vulnerability exists due to an incomplete fix…
CVE-2008-7313 — Critical (CVSS 9.8): The _httpsrequest function in Snoopy allows remote attackers to execute arbitrary commands. NOTE: this issue exists…
CVE-2016-9565 — Critical (CVSS 9.8): MagpieRSS, as used in the front-end component in Nagios Core before 4.2.2 might allow remote attackers to read or write…

All CVEs affecting Nagios →

Other CWE-59 (Improper Link Resolution Before File Access (Link Following)) vulnerabilities

CVE-2024-37143 — Critical (CVSS 10.0): Dell PowerFlex appliance versions prior to IC 46.381.00 and IC 46.376.00, Dell PowerFlex rack versions prior to RCM…
CVE-2024-28189 — Critical (CVSS 10.0): Judge0 is an open-source online code execution system. The application uses the UNIX chown command on an untrusted file…
CVE-2024-28185 — Critical (CVSS 10.0): Judge0 is an open-source online code execution system. The application does not account for symlinks placed inside the…
CVE-2022-22995 — Critical (CVSS 10.0): The combination of primitives offered by SMB and AFP in their default configuration allows the arbitrary writing of…
CVE-2014-4480 — Critical (CVSS 10.0): Directory traversal vulnerability in afc in AppleFileConduit in Apple iOS before 8.1.3 and Apple TV before 7.0.3 allows…
CVE-2002-2374 — Critical (CVSS 10.0): Unspecified vulnerability in pprosetup in Sun PatchPro 2.0 has unknown impact and attack vectors related to "unsafe use…

Browse all CWE-59 (Improper Link Resolution Before File Access (Link Following)) vulnerabilities →