Checkmk XSS Flaw: How Not to Trust Your Monitoring System Until It Behaves!
Checkmk users, beware! Before version 2.4.0p14, your distributed monitoring setup could be a playground for mischievous JavaScript. This cross-site scripting flaw (CVE-2025-39663) lets remote sites inject code into the central UI. Update to keep your servers from becoming the next star in a hacker comedy show.
Hot Take:
Oh, Checkmk, you’ve really outdone yourself this time! Not only have you managed to make Cross Site Scripting sound like a fun new feature, but you’ve also turned web monitoring into a game of “Who’s Got the Hacker?”. It’s like playing tag, but with JavaScript injections instead of friendly pats. Who knew IT monitoring could be so interactive?
Key Points:
- Checkmk versions before 2.4.0p14 and 2.3.0p39 are vulnerable to Stored XSS.
- The vulnerability allows attackers to inject JavaScript into the central user interface from remote sites.
- Attackers can exploit admin sessions, potentially leading to remote code execution.
- Checkmk has released fixes in versions 2.4.0p14 and 2.3.0p39.
- Disabling the “Trust this site completely” option is recommended for security.
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