CVE-2025-64999 | Cross-site scripting in HTML logs of Synthetic Monitoring test services

Improper neutralization of input in Checkmk versions 2.4.0 before 2.4.0p22, and 2.3.0 before 2.3.0p43 allows an attacker that can manipulate a host's check output to inject malicious JavaScript into the Synthetic Monitoring HTML logs, which can then be accessed via a crafted phishing link.

Published: 2026-02-26 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-64999 is rated Low Risk (30.6/100): CVSS High severity, with low exploitation likelihood (EPSS 0.14%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-64999

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.05% 0.14% +0.09%
2 2026-02-26 — 0.05% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-64999

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.3 4.0 HIGH
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:P)
Additional preconditions must be present for exploitation.
Privileges required (PR:L)
Low privileges are required.
User interaction (UI:A)
User interaction is required in an active way.
Vulnerable system confidentiality impact (VC:H)
High confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:H)
High integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:H)
High availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:L)
Limited integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — [email protected]
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 2.7 [email protected]

Weakness enumeration for CVE-2025-64999

OS Trackers for CVE-2025-64999

vendor priority summary link
ubuntu medium CVE-2025-64999 medium priority: Ubuntu including 1 source packages (check-mk), 6 status rows across 6 suites (bionic, jammy, noble, questing, upstream, xenial): DNE 3, needs-triage 3. https://ubuntu.com/security/CVE-2025-64999

Affected software / configurations for CVE-2025-64999

Vendor Product Version Raw CPE
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:-:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:b1:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:b2:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:b3:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:b4:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:b5:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:b6:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p1:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p10:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p11:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p12:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p13:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p14:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p15:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p16:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p17:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p18:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p19:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p2:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p20:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p21:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p22:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p23:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p24:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p25:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p26:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p27:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p28:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p29:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p3:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p30:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p31:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p32:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p33:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p34:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p35:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p36:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p37:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p38:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p39:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p4:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p40:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p41:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p42:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p5:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p6:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p7:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p8:*:*:*:*:*:*
checkmk checkmk 2.3.0 cpe:2.3:a:checkmk:checkmk:2.3.0:p9:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:-:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:b1:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:b2:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:b3:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:b4:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:b5:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:b6:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p1:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p10:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p11:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p12:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p13:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p14:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p15:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p16:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p17:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p18:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p19:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p2:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p20:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p21:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p3:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p4:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p5:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p6:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p7:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p8:*:*:*:*:*:*
checkmk checkmk 2.4.0 cpe:2.3:a:checkmk:checkmk:2.4.0:p9:*:*:*:*:*:*

References for CVE-2025-64999

cvelogic Threat Intelligence