PT-2026-22137 · Checkmk · Checkmk

Lisa Gnedt · CVE-2025-64999 · Published 2026-02-26 · Updated 2026-03-05

Positive Technologies (AI Summary)

CVSS v4.0

7.3

High

Base vector

AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N

Name of the Vulnerable Software and Affected Versions Checkmk versions 2.3.0 through 2.3.0p43 Checkmk versions 2.4.0 through 2.4.0p22

Description The software contains a flaw due to improper neutralization of input. An attacker who can manipulate a host's check output can inject malicious JavaScript into the Synthetic Monitoring HTML logs. This injected code can then be accessed through a specially crafted phishing link.

Recommendations Update Checkmk to version 2.3.0p43 or later. Update Checkmk to version 2.4.0p22 or later.

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2025-64999

Affected Products

Checkmk

References · 13

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/64xxx/CVE-2025-64999.json · Exploit
• https://cve.org/CVERecord?id=CVE-2025-64999 · Security Note
• https://osv.dev/vulnerability/UBUNTU-CVE-2025-64999 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2025-64999 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-64999 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-64999 · Security Note
• https://checkmk.com/werk/19238 · Vendor Advisory
• https://github.com/sbaresearch/advisories/tree/e72ce9bb6b9ffffc1fc35e4d8152ad153293c851/2025/SBA-ADV-20251118-01_Checkmk_Cross_Site_Scripting · Note
• https://t.me/cveNotify/153301 · Telegram Post
• https://t.me/cveNotify/153726 · Telegram Post
• https://twitter.com/CVEnew/status/2027004181173727283 · Twitter Post
• https://t.me/CVEtracker/45844 · Telegram Post
• https://t.me/cveNotify/154337 · Telegram Post