CVE-2026-4637

NVD: Paessler PRTG Network Monitor before version 26.2.120.1449 is affected by a reflected Cross-Site Scripting (XSS) vulnerability. NVD: When a request is made for a non-existent resource ending in \".htm\", the web interface returns an HTTP 403 \"Forbidden Path\" error page that echoes the requested URL path into the HTML response body without proper output encoding or sanitization. NVD: and, once a victim with an active PRTG session opens the crafted link, execute arbitrary JavaScript in the security context of the PRTG web interface.

Source-published summary

NVD: Paessler PRTG Network Monitor before version 26.2.120.1449 is affected by a reflected Cross-Site Scripting (XSS) vulnerability. NVD: When a request is made for a non-existent resource ending in \".htm\", the web interface returns an HTTP 403 \"Forbidden Path\" error page that echoes the requested URL path into the HTML response body without proper output encoding or sanitization. NVD: and, once a victim with an active PRTG session opens the crafted link, execute arbitrary JavaScript in the security context of the PRTG web interface.

Possible impact

This medium severity issue needs human triage to confirm exposure, affected versions, and vendor guidance for defensive exposure review.

Affected context

Affected product or version requires source confirmation.

Remediation / advisory

Remediation reference present; patch status requires confirmation in the linked advisory.

Why it matters

This medium severity issue needs human triage to confirm exposure, affected versions, and vendor guidance for defensive exposure review.; CVSS 5.1 (MEDIUM); EPSS percentile 44; not listed in KEV; Remediation reference present; patch status requires confirmation in the linked advisory; sources: NVD.

What to verify

Confirm affected product/version, vendor advisory, patch or mitigation, and exposure.

Exposure hint

exposure unknown

Impact tags

Urgency reasons

Source-derived note

Summary derived from NVD description; unsafe procedural detail is not shown.

Redaction metadata

source summary used

True

fallback summary used

False

unsafe procedural detail present

false

raw source displayed

false

public summary redacted

true

Remediation handoff

Public-safe static handoff for human/Codex remediation planning. Scan, patch, external execution, and auto remediation are disabled.

Safety note

This radar shows source-published defensive context only. Exploit procedures, exploit strings, scanner commands, and auto-remediation are not provided.

Official references

• https://nvd.nist.gov/vuln/detail/CVE-2026-4637
• https://sec-consult.com/vulnerability-lab/advisory/multiple-vulnerabilities-in-paessler-prtg-network-monitor/