OT/ICS web UI vulnerability enabling remote manipulation of PLCs; impacts industrial control systems and could disrupt operations, making it high-profile for infrastructure owners.
CVE-2026-63353
Stored XSS in PLC trace import allows JS execution and unauthorized PLC actions.
Is CVE-2026-63353 being exploited?
Not confirmed. CVE-2026-63353 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.41% probability of exploitation in the next 30 days.
How severe is CVE-2026-63353?
CVE-2026-63353 is rated Critical with a CVSS score of 9.4. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-63353?
Not known from our data. No patch reference has been recorded for CVE-2026-63353, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-63353 affect?
CVE-2026-63353 affects Siemens devices with web-based Trace page, Devices accepting trace file imports, Accounts with 'Read diagnostics' privilege. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-63353?
Block/unpublish trace import, remove 'Read diagnostics' rights from nonessential users, isolate PLC web UI, apply vendor patch when released
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker can trick a user to import a crafted trace file, run attacker-controlled JS in the user's browser, and issue PLC commands within that user's authorization.
Immediate action required
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
- affected< *
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.