PT-2026-21677 · Unknown · Iec 60870-5-104

Published 2026-02-24 · Updated 2026-03-01 · CVE-2026-1773

Positive Technologies (AI Summary)

CVSS v4.0

8.7

High

Base vector

AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Name of the Vulnerable Software and Affected Versions IEC 60870-5-104 (affected versions not specified)

Description The software may experience a denial of service when receiving invalid U-format frames. The issue affects products only if the IEC 60870-5-104 bi-directional functionality is configured. While enabling secure communication following IEC 62351-3 does not resolve the issue, it can reduce the risk of exploitation.

Recommendations Configure the bi-directional function carefully. Enable secure communication following IEC 62351-3 to mitigate the risk of exploitation.

Fix

DoS

RCE

Incomplete List of Disallowed Inputs

Weakness Enumeration

CWE-20

CWE-184

Related Identifiers

CVE-2026-1773

Affected Products

Iec 60870-5-104

References · 8

• https://nvd.nist.gov/vuln/detail/CVE-2026-1773 · Security Note
• https://osv.dev/vulnerability/CVE-2026-1773 · Vendor Advisory
• https://publisher.hitachienergy.com/preview?DocumentID=8DBD000237&LanguageCode=en&DocumentPartId=&Action=Launch · Vendor Advisory
• https://twitter.com/cracbot/status/2027700483692105868 · Twitter Post
• https://twitter.com/cracbot/status/2028062794344812551 · Twitter Post
• https://t.me/cveNotify/153558 · Telegram Post
• https://twitter.com/CveFindCom/status/2026298817784504610 · Twitter Post
• https://twitter.com/CVEnew/status/2027841530883674386 · Twitter Post