CVE-2026-20915
Stored cross-site scripting (XSS) in Checkmk version 2.5.0 (beta) before 2.5.0b2 allows authenticated users with permission to create pending changes to inject malicious JavaScript into the Pending Changes sidebar, which will execute in the browsers of other users viewing the sidebar.
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exploitation prediction scoring system. probability this vulnerability will be exploited in the wild in the next 30 days.
cvss
common vulnerability scoring system v3.1. measures intrinsic severity on a 0-10 scale.
epss
0.0003
kev
no
cisa known exploited vulnerabilities catalog. confirmed active exploitation.
CVSS 3.1
Common Vulnerability Scoring System v3.1
5.4
/ 10
MEDIUM
exploitability
Attack Vector
Network
Attack Vector (AV:N): exploitable remotely over the network — most dangerous. no physical or adjacent access needed.
Attack Complexity
Low
Attack Complexity (AC:L): no special conditions needed. attack can be reliably reproduced.
Privileges Required
Low
Privileges Required (PR:L): requires basic user-level access.
User Interaction
Required
User Interaction (UI:R): victim must perform some action (e.g. clicking a link, opening a file).
impact
Scope
Changed
Scope (S:C): exploitation impacts resources beyond the vulnerable component.
Confidentiality
Low
Confidentiality (C:L): limited data exposure. some restricted information can be read.
Integrity
Low
Integrity (I:L): limited data modification. some data can be altered.
Availability
None
Availability (A:N): no availability impact.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CVSS 4.0
Common Vulnerability Scoring System v4.0
8.5
/ 10
HIGH
exploitability
Attack Vector
Network
Attack Vector (AV:N): exploitable remotely over the network — most dangerous. no physical or adjacent access needed.
Attack Complexity
Low
Attack Complexity (AC:L): no special conditions needed. attack can be reliably reproduced.
Attack Requirements
None
Attack Requirements (AT:N): no special deployment or execution conditions needed.
Privileges Required
High
Privileges Required (PR:H): requires admin or highly privileged access.
User Interaction
Passive
User Interaction (UI:P): victim must perform a limited, passive action (e.g. opening a document).
vulnerable system impact
Vuln Confidentiality
High
Confidentiality (VC:H): total information disclosure. attacker gains access to all data within the component.
Vuln Integrity
High
Integrity (VI:H): complete data modification possible. attacker can modify any data.
Vuln Availability
High
Availability (VA:H): total denial of service. attacker can fully shut down the resource.
subsequent system impact
Sub Confidentiality
None
Subsequent Confidentiality: impact on data confidentiality of downstream/connected systems. Value: N (None)
Sub Integrity
Low
Subsequent Integrity: impact on data integrity of downstream/connected systems. Value: L (Low)
Sub Availability
None
Subsequent Availability: impact on service availability of downstream/connected systems. Value: N (None)
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/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
activity density
rdintel assessment
composite score from 15+ signals including exploitation status, epss probability, detection coverage, and community attention. 0-100 scale.
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