CVE-2025-39665: User enumeration in Nagvis' Checkmk MultisiteAuth before version 1.9.48 allows an unauthenticated attacker to

Q: How do I fix CVE-2025-39665?

nagvis: upgrade to 1.9.48. Exact commands for each OS are on this page.

Q: Is CVE-2025-39665 being exploited?

CVE-2025-39665 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-39665 affect?

CVE-2025-39665 affects nagvis. Severity is medium (CVSS 5.3). User enumeration in Nagvis' Checkmk MultisiteAuth before version 1.9.48 allows an unauthenticated attacker to enumerate Checkmk usernames.

Q: How urgent is CVE-2025-39665?

Priority 28/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2025-39665 is a medium-severity flaw (CVSS 5.3) affecting nagvis. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

User enumeration in Nagvis' Checkmk MultisiteAuth before version 1.9.48 allows an unauthenticated attacker to enumerate Checkmk usernames.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 83%)
CISA exploited list	No
Weakness	CWE-203
Published	2025-12-03
Last modified	2026-10-18

Publisher (CNA): Checkmk GmbH · Vendor: nagvis

Last updated 2026-10-18 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-12-03 10:15 UTCPublished CVE record published
2026-10-18 18:10 UTCUpdated Record last modified

nagvis nagvis UPGRADE

Affected: < 1.9.48

Fixed in: 1.9.48

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy nagvis || rpm -q nagvis || nagvis --version

2. UPGRADE to 1.9.48 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nagvis

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nagvis

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-39665?

nagvis: upgrade to 1.9.48. Exact commands for each OS are on this page.

Is CVE-2025-39665 being exploited?

CVE-2025-39665 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-39665 affect?

CVE-2025-39665 affects nagvis. Severity is medium (CVSS 5.3). User enumeration in Nagvis' Checkmk MultisiteAuth before version 1.9.48 allows an unauthenticated attacker to enumerate Checkmk usernames.

How urgent is CVE-2025-39665?

Priority 28/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2024-47093 HIGH 8.8 UPGRADE Improper neutralization of input in Nagvis before version 1.9.42 which can lead to XSS
CVE-2024-47090 MEDIUM 6.1 UPGRADE Improper neutralization of input in Nagvis before version 1.9.47 which can lead to XSS
CVE-2024-38866 HIGH 7.5 UPGRADE Improper neutralization of input in Nagvis before version 1.9.47 which can lead to livestatus injection

References

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