CVE intelligence and bounded remediation

CVE-2026-1773 — IEC 60870-5-104 used in RTU500: Potential Denial of Service impact on reception of invalid U-format frame

High CVSS 8.7

IEC 60870-5-104 used in RTU500: Potential Denial of Service impact on reception of invalid U-format frame. Product is only affected if IEC 60870-5-104 bi-directional functionality is configured. Enabling secure communication following IEC 62351-3 does not remediate the vulnerability but mitigates the risk of exploitation.

Severity
High
CVSS
8.7 (4.0)
Published
2026-02-24
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-184

Affected products

  • hitachienergy / rtu540_firmware
  • hitachienergy / rtu540_firmware / 13.8.1
  • hitachienergy / rtu560_firmware
  • hitachienergy / rtu560_firmware / 13.8.1
  • hitachienergy / rtu520_firmware

Showing 5 representative product identities from 20 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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