Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:N) | Network: reachable remotely |
| Attack complexity (AC:L) | Low complexity |
| Attack requirements (AT:P) | Attack requirements present |
| Privileges required (PR:H) | High privileges required |
| User interaction (UI:P) | Passive user interaction |
| Confidentiality (VC:H) | High confidentiality impact |
| Integrity (VI:H) | High integrity impact |
| Availability (VA:H) | High availability impact |
CVSS:4.0/AV:N/AC:L/AT:P/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
About Checkmk
CVE-2025-64998 affects Checkmk, a product from Checkmk. Before acting, confirm where Checkmk runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: Exposure of session signing secret in Checkmk <2.4.0p23, <2.3.0p45 and 2.2.0 allows an administrator of a remote site with config sync enabled to hijack sessions on the central site by forging session cookies.
Based on its CVSS vector, the flaw can be reached over the network, needs some level of access, and relies on a user taking an action. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Checkmk |
| Affected versions | Checkmk 2.2.0; Checkmk 2.3.0; Checkmk 2.4.0 |
| Published | Mar 24, 2026 |
| Last modified | Jun 17, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | security@checkmk.com |
How to detect it
- Inventory every instance of Checkmk and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Checkmk named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Checkmk to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
Technical References
Frequently asked questions
Related CVEs
Local privilege escalation 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 2.5.0b3 allows a site user to escalate their privileges to root, by manipulating files in the site context that are processed when the `omd` administrative command is run by root.
CWE‑522: Insufficiently Protected Credentials in web services in Progress Sitefinity version from 14.0.7700 to 14.4.8152, and 15.0.8200 to 15.0.8234, and 15.1.8300 to 15.1.8335, 15.2.8400 to 15.2.8441, 15.3.8500 to 15.3.8531, and 15.4.8600 to 15.4.8630 allows a remote unauthenticated attacker to obtain plain-text credentials used connect to Sitefinity Insight service. Successful exploitation requires active integration with Sitefinity Insight and non-default site configuration.
The vulnerability exists in BLUVOYIX due to an improper password storage implementation and subsequent exposure via unauthenticated APIs. An unauthenticated remote attacker could exploit this vulnerability by sending specially crafted HTTP requests to the vulnerable users API to retrieve the plaintext passwords of all user users. Successful exploitation of this vulnerability could allow the attacker to gain full access to customers' data and completely compromise the targeted platform by logging in using an exposed admin email address and password.
Coolify is an open-source and self-hostable tool for managing servers, applications, and databases. In Coolify versions prior to and including v4.0.0-beta.434, low privileged users are able to see the private key of the root user on the Coolify instance. This allows them to ssh to the server and authenticate as root user, using the private key. As of time of publication, it is unclear if a patch is available.
siyuan versions before v3.7.4 expose the session cookie signing key through the /api/system/getConf endpoint to unauthenticated users in publish mode. Attackers can retrieve the CookieKey value and forge valid session cookies to impersonate users or gain administrative access.
Flowise is a drag & drop user interface to build a customized large language model flow. Prior to version 3.1.2, the checkBasicAuth endpoint validates credentials in plaintext without rate limiting and with direct comparison. This issue has been patched in version 3.1.2.
Earn your free CTEM certification.
Learn to scope, prioritize, validate and mobilize fixes for CVEs like CVE-2025-64998 with a free CTEM certification.
Beginner / Practitioner / Program Leader
Explore certifications