CVE-2026-34021
RS-485 lacks crypto; sniff/replay enables quit alarm spoof and safe disable.
Is CVE-2026-34021 being exploited?
Not confirmed. CVE-2026-34021 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 0.20% probability of exploitation in the next 30 days.
How severe is CVE-2026-34021?
CVE-2026-34021 is rated High with a CVSS score of 8.6. 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-2026-34021?
Yes. A fix has been recorded for CVE-2026-34021. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-34021 affect?
CVE-2026-34021 affects Wertheim SafeController 5400 (Controller 5400, AssemblyVersion 6.11.8130.22320). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-34021?
Implement crypto/auth on RS-485 and segment the bus; restrict physical access.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
RS-485 traffic can be sniffed and replayed to spoof quit alarm and keep safety deactivated.
Immediate action required
- affectedWertheim SafeController 5400, Controller 5400 - AssemblyVersion 6.11.8130.22320
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.