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Vulnerability record · CVE-2021-25663 · published 22 April 2021

CVE-2021-25663: Siemens capital vstar vulnerability

Siemens · Capital Vstar

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.

8.7 CVSS 4.0 High EPSS 1.9% · top 21.3% CWE-835 · CWE-835
8.7CVSS 4.0 base score, v2 5.0
1.9%EPSS exploitation probability, 30 days
NoNot in CISA KEV
4Affected product versions listed by NVD
6References
17 Jun 2026Last modified by NVD

Description

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.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

4 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://cert-portal.siemens.com/productcert/html/ssa-248289.html
https://cert-portal.siemens.com/productcert/pdf/ssa-248289.pdf Vendor Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-103-05 Third Party AdvisoryUS Government Resource
https://cert-portal.siemens.com/productcert/html/ssa-248289.html
https://cert-portal.siemens.com/productcert/pdf/ssa-248289.pdf Vendor Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-103-05 Third Party AdvisoryUS Government Resource

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2021-31884Siemens capital vstar vulnerabilityA vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BAC…EPSS 1.5%9.8CVE-2021-31886Siemens nucleus net out-of-bounds write vulnerabilityA vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BAC…EPSS 3.0%9.1CVE-2021-31345Siemens capital vstar vulnerabilityA vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic R20-11 (All versions < V2303),…EPSS 1.6%9.1CVE-2021-31346Siemens capital vstar vulnerabilityA vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic R20-11 (All versions < V2303),…EPSS 2.0%9.1CVE-2021-31889Siemens capital vstar vulnerabilityA vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic R20-11 (All versions < V2303),…EPSS 2.2%9.1CVE-2021-31890Siemens capital vstar vulnerabilityA vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic R20-11 (All versions < V2303),…EPSS 2.2%8.8CVE-2021-31887Siemens nucleus net out-of-bounds write vulnerabilityA vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BAC…EPSS 2.4%8.8CVE-2021-31888Siemens nucleus net out-of-bounds write vulnerabilityA vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BAC…EPSS 2.4%

Source: NIST National Vulnerability Database (record CVE-2021-25663), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.