What’s Vulnerable › Vulnerabilities

CVE-2021-20988: Hilscher rcX RTOS: Wrong handling of the UDP checksum

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-05-13 · updated 2026-06-17
• Weakness: CWE-119

Description

In Hilscher rcX RTOS versions prios to V2.1.14.1 the actual UDP packet length is not verified against the length indicated by the packet. This may lead to a denial of service of the affected device.

Affected products

• Hilscher rcX RTOS: before 2.1.14.1 — fixed in 2.1.14.1
• Pepperl-Fuchs Ice1-16Di-G60L-V1D Firmware: through f10017
• Pepperl-Fuchs Ice1-16Dio-G60L-C1-V1D Firmware: through f10017
• Pepperl-Fuchs Ice1-16Dio-G60L-V1D Firmware: through f10017
• Pepperl-Fuchs Ice1-8Di8Do-G60L-C1-V1D Firmware: through f10017
• Pepperl-Fuchs Ice1-8Di8Do-G60L-V1D Firmware: through f10017
• Pepperl-Fuchs Ice1-8Iol-G30L-V1D Firmware: through f10017
• Pepperl-Fuchs Ice1-8Iol-G60L-V1D Firmware: through f10017
• Pepperl-Fuchs Ice1-8Iol-S2-G60L-V1D Firmware: through f10017

How to fix

Upgrade to a fixed version: Hilscher rcX RTOS 2.1.14.1. Check the vendor advisory for mitigations.

References

• https://cert.vde.com/de-de/advisories/vde-2021-018
• https://kb.hilscher.com/display/ISMS/2019-04-10+Wrong+handling+of+the+UDP+checksum
• https://cert.vde.com/de-de/advisories/vde-2021-018
• https://kb.hilscher.com/display/ISMS/2019-04-10+Wrong+handling+of+the+UDP+checksum

Get alerted when CVE-2021-20988 or the next vulnerability affects your stack