CVE Vulnerabilities

CVE-2021-25663

Loop with Unreachable Exit Condition ('Infinite Loop')

Published: Apr 22, 2021 | Modified: Jun 17, 2026
CVSS 3.x
7.5
HIGH
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
5 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P
RedHat/V2
RedHat/V3
Ubuntu

A vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic R20-11 (All versions < V2303), Nucleus NET (All versions), Nucleus ReadyStart V3 (All versions < V2017.02.4), Nucleus ReadyStart V4 (All versions < V4.1.0), Nucleus Source Code (All versions including affected IPv6 stack). The function that processes IPv6 headers does not check the lengths of extension header options, allowing attackers to put this function into an infinite loop with crafted length values.

Weakness

The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

Affected Software

NameVendorStart VersionEnd Version
Capital_vstarSiemens- (including)- (including)
Nucleus_netSiemens**
Nucleus_readystartSiemens*4.1.0 (excluding)
Nucleus_source_codeSiemens- (including)- (including)

References