Loading vulnerabilities…
Loading vulnerabilities…
CVE-2020-35685
An issue was discovered in HCC Nichestack 3.0. The code that generates Initial Sequence Numbers (ISNs) for TCP connections derives the ISN from an insufficiently random source. As a result, an attacker may be able to determine the ISN of current and future TCP connections and either hijack existing ones or spoof future ones. (Proper ISN generation should aim to follow at least the specifications outlined in RFC 6528.)
This record: live connection— last retrieved: 7 November 2026 at 03:37.
Vendor
Products
Base-Device PNOZ mxp ETH (PNOZmulti Classic), PNOZ m B1, PNOZ m ES ETH, PNOZ mmc1p ETH, PSSu-Module for decentralised E/A-System, PSSu-Module for PSS 4000
up to version vers:all/*
Published
19 August 2021
Last modified
17 June 2026
Taken directly from NVD, CISA or the vendor — sometimes in English, unchanged from the source.
An issue was discovered in HCC Nichestack 3.0. The code that generates Initial Sequence Numbers (ISNs) for TCP connections derives the ISN from an insufficiently random source. As a result, an attacker may be able to determine the ISN of current and future TCP connections and either hijack existing ones or spoof future ones. (Proper ISN generation should aim to follow at least the specifications outlined in RFC 6528.)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack vector
NETWORK
Privileges required
NONE
User interaction
NONE
Confidentiality
High
Integrity
High
Availability
None
Probability of exploitation within 30 days
2.1%
Percentile
81e
Source: FIRST.org, updated on 6 November 2026.
It is adviced to use firewalls or similar network security devices to prevent unauthorized network communication to the products affected.
Our own interpretation and context for the source data above.
IACS Radar assessment
Our own interpretation and context for this vulnerability — not an official source.
IACS Radar priority score
Based on CVSS 9.1, EPSS 2.1%, industrial relevance 40/100.
Combines CVSS, EPSS, KEV status, industrial relevance and exposure relevance — a complement to, not a replacement for, the individual scores below and above.
Conditions for exploitation
Operational impact & energy relevance
Limited impact on availability; the risk lies mainly with confidentiality or integrity of process data.
No strong energy-sector-specific signals recognised; general OT/ICS relevance.
Recommended defensive measures
Industrial relevance score
Classification is provisional; manual verification by an OT security analyst is recommended.
Classified by IACS Radar-analysepijplijn (geautomatiseerd) on 7 November 2026.
IEC 62443 mapping
Automatic IACS Radar assessment based on the reported CWE weakness classification; not an official certification statement.