Severity: CriticalAction: Patch
Siemens SIMATIC S7 PLCs Web Server
Patch
Apply the vendor's security update for the affected products.
Vulnerability record
CVE-2026-63351
Severity: ElevatedExploitation: No known exploitation
Patch status
No official fix confirmed yet
Until a fix ships, follow the vendor's mitigations, limit exposure of affected systems, and watch this record for a patch.
Description
Affected devices do not properly validate and sanitize visual properties of calculated signals contained in imported CSV trace files before rendering them on the Trace page. This could allow an attacker to social engineer an authorized user who holds the function right “Read diagnostics” into importing a specially crafted trace file. Successful exploitation could allow attacker-controlled JavaScript to execute in the user’s browser session and perform PLC operations through the web server within the scope of the user’s authorization.
Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.
Intelligence timeline
Developments from the last 30 days, newest first.
- CVSS scoredUpdate
CVE-2026-63351 scored CVSS 5.3
Basis: NIST National Vulnerability Database