CVE-2026-48552 Nagios Core / XI DOM-based XSS via jsonquery.js
Attackers can execute arbitrary JavaScript in victims' browsers via DOM-based XSS in Nagios Core and XI, potentially leading to session hijacking or malicious actions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-48552?
CVE-2026-48552 is a medium-severity cross-site scripting vulnerability in Nagios Core, published on 12 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Nagios Core before 4.5.14 and Nagios XI before 2026R1.7 are vulnerable to DOM-based cross-site scripting in jsonquery.js. Unencoded JSON string values reflected from stored fields are inserted into the DOM without sanitization, allowing attackers to run arbitrary JavaScript in the victim's browser.
Weakness: CWE-79
Which versions are affected by CVE-2026-48552?
How do I fix CVE-2026-48552?
Upgrade to a fixed version.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-48552 being exploited?
There is no known exploitation of CVE-2026-48552 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-48552, GHSA-m927-w885-wph8, UBUNTU-CVE-2026-48552.