# 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.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N`)
- **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:** Yes
- **Published:** 12 Aug 2026
- **Updated:** 14 Aug 2026
- **Also known as:** DEBIAN-CVE-2026-48552, GHSA-m927-w885-wph8, UBUNTU-CVE-2026-48552

## 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 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-48552?


## How do I fix CVE-2026-48552?

Upgrade to a fixed version.

## Is CVE-2026-48552 being exploited?

There is no known exploitation of CVE-2026-48552 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48552 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-48552 in the wild and no public exploit code.

Affected product: Nagios Core. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-48552/ (Markdown: https://insights.sbomify.com/CVE-2026-48552/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48552
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48552
- OSV: https://osv.dev/vulnerability/CVE-2026-48552

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48552/
Summaries are generated and may contain mistakes; the official description above is the record.