CVE-2026-3466 [High] | XSS in Checkmk

Insufficient sanitization of dashboard dashlet title links in Checkmk 2.2.0 (EOL), Checkmk 2.3.0 before 2.3.0p46, Checkmk 2.4.0 before 2.4.0p25, and Checkmk 2.5.0 (beta) before 2.5.0 allows an attacker with dashboard creation privileges to perform stored cross-site scripting (XSS) attacks by tricking a victim into clicking a crafted dashlet title link on a shared dashboard.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-04-15	0.05%	0.03%	-0.02%
2	2026-04-13	0.05%	0.05%	+0.00%
3	2026-04-08	—	0.05%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-04-15

0.05%

0.03%

-0.02%

2026-04-13

0.05%

+0.00%

2026-04-08

—

0.05%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
8.5	4.0	HIGH	`CVSS:4.0/AV:N/AC:L/AT:N/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:N) No additional preconditions are required beyond normal reachability. 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]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

8.5

4.0

HIGH

CVSS:4.0/AV:N/AC:L/AT:N/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:N): No additional preconditions are required beyond normal reachability.
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]

OS Trackers for CVE-2026-3466

vendor	priority	summary	link
`ubuntu`	medium	CVE-2026-3466 medium priority: Ubuntu including 1 source packages (check-mk), 7 status rows across 7 suites (bionic, jammy, noble, questing, resolute, upstream, xenial): DNE 4, needs-triage 3.	https://ubuntu.com/security/CVE-2026-3466

Affected software / configurations for CVE-2026-3466

Vendor	Product	Version	Raw CPE
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:-::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:b1::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:b2::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:b3::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:b4::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:b5::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:b6::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:b7::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:b8::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:i1::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p1::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p10::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p11::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p12::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p13::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p14::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p15::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p16::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p17::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p18::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p19::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p2::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p20::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p21::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p22::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p23::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p24::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p25::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p26::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p27::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p28::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p29::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p3::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p30::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p31::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p32::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p33::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p34::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p35::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p36::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p37::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p38::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p39::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p4::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p40::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p41::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p42::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p43::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p44::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p45::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p46::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p47::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p5::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p6::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p7::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p8::::::
checkmk	checkmk	2.2.0	cpe:2.3:a:checkmk:checkmk:2.2.0:p9::::::
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::::::

References for CVE-2026-3466

URL	Tags
https://checkmk.com/werk/19033	Vendor Advisory
https://checkmk.com/werk/19583
https://www.vulncheck.com/advisories/checkmk-stored-cross-site-scripting-in-dashlet-title	Release Notes Third Party Advisory

URL

CVE-2026-3466 | Cross-site scripting in dashlet title

Exploit prediction scoring system (EPSS) score for CVE-2026-3466

Common vulnerability scoring system (CVSS) metrics for CVE-2026-3466

Weakness enumeration for CVE-2026-3466

GitHub Security Advisory for CVE-2026-3466

OS Trackers for CVE-2026-3466

Affected software / configurations for CVE-2026-3466

References for CVE-2026-3466