CVE-2026-20915 json
Stored cross-site scripting in Pending Changes sidebar
published 2026-03-31 7 mo ago modified 2026-07-25 3 mo ago also EUVD-2026-17417
- cvss
- 5.4
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 4%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- Checkmk GmbH Checkmk 2.5.0b2
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 7 mo ago
Exploit prediction
0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.5 | 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 |
| CNA | 4.0 | 8.5 | 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 |
| NVD | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
Affected products
- Checkmk GmbH Checkmk
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
checkmk.com
/werk/19526
vendor-advisory
Sources
- CVE List CVE-2026-20915
- NVD CVE-2026-20915
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.