CVE-2025-39663 | Cross Site Scripting through compromised remote site

Exp

Cross-Site Scripting (XSS) vulnerability in Checkmk's distributed monitoring allows a compromised remote site to inject malicious HTML code into service outputs in the central site. Affecting Checkmk before 2.4.0p14, 2.3.0p39, 2.2.0 and 2.1.0 (eol).

Published: 2025-10-30 Last update: 2025-12-03 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-39663 is rated Exploit Available (55.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.06%). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2025-39663

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2025-39663

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 2025-12-11 0.04% 0.06% +0.01%
2 2025-12-04 0.06% 0.04% -0.02%
3 2025-11-05 — 0.06% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-39663

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.5 4.0 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/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:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:H)
High privileges are required.
User interaction (UI:P)
A user has to participate (for example click/open/approve).
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:N)
No 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]
8.4 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H 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:H)
They need powerful rights—admin, root, or similar—before this pays off.
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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.7 6.0 [email protected]

Weakness enumeration for CVE-2025-39663

OS Trackers for CVE-2025-39663

vendor priority summary link
ubuntu medium CVE-2025-39663 medium priority: Ubuntu including 1 source packages (check-mk), 7 status rows across 7 suites (bionic, jammy, noble, plucky, questing, upstream, xenial): DNE 4, needs-triage 3. https://ubuntu.com/security/CVE-2025-39663

Affected software / configurations for CVE-2025-39663

Vendor Product Version Raw CPE
checkmk checkmk >= 2.0.0, < 2.3.0 cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*
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: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:p4:*:*:*:*:*:*
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: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:p2:*:*:*:*:*:*
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:p9:*:*:*:*:*:*

References for CVE-2025-39663

cvelogic Threat Intelligence