CVE-2026-20915 | Checkmk up to 2.5.0b1 cross site scripting

VDB-354409 · CVE-2026-20915 · GCVE-0-2026-20915 CHECKMK UP TO 2.5.0B1 CROSS SITE SCRIPTING HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 2.3 $0-$5k 2.54+ Summaryinfo A vulnerability classified as problematic has been found in Checkmk up to 2.5.0b1. Affected by this vulnerability is an unknown functionality. This manipulation causes cross site scripting. The identification of this vulnerability is CVE-2026-20915. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to upgrade the affected component. Detailsinfo A vulnerability was found in Checkmk up to 2.5.0b1. It has been declared as problematic. Affected by this vulnerability is some unknown processing. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. The summary by CVE is: 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. The advisory is shared at checkmk.com. This vulnerability is known as CVE-2026-20915 since 03/23/2026. The exploitation appears to be easy. The attack can be launched remotely. Additional levels of successful authentication are needed for exploitation. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue. Upgrading to version 2.5.0b2 eliminates this vulnerability. Productinfo Name Checkmk Version 2.5.0b1 CPE 2.3info 🔒 CPE 2.2info 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA CVSS-B Score: 🔒 CNA CVSS-BT Score: 🔒 CNA Vector: 🔒 CVSSv3info VulDB Meta Base Score: 2.4 VulDB Meta Temp Score: 2.3 VulDB Base Score: 2.4 VulDB Temp Score: 2.3 VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Cross site scripting CWE: CWE-79 / CWE-94 / CWE-74 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Yes Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: Checkmk 2.5.0b2 Timelineinfo 03/23/2026 CVE reserved 03/31/2026 +7 days Advisory disclosed 03/31/2026 +0 days VulDB entry created 03/31/2026 +0 days VulDB entry last update Sourcesinfo Advisory: checkmk.com Status: Confirmed CVE: CVE-2026-20915 (🔒) GCVE (CVE): GCVE-0-2026-20915 GCVE (VulDB): GCVE-100-354409 Entryinfo Created: 03/31/2026 17:05 Changes: 03/31/2026 17:05 (65) Complete: 🔍 Cache ID: 99:E99:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸