How severe is CVE-2021-31345?

CVE-2021-31345 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2021-31345 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-31345?

CVE-2021-31345 primarily affects Siemens Capital Vstar. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-31345?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-31345 published?

CVE-2021-31345 was published on 2021-11-09 and last updated on 2026-06-17.

CVE-2021-31345

CVE-2021-31345 is a high-severity vulnerability in Siemens Capital Vstar with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1284.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 6.4
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1284
Affected product: Siemens Capital Vstar
Published: 2021-11-09
Last modified: 2026-06-17

Description

A vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic R20-11 (All versions < V2303), PLUSCONTROL 1st Gen (All versions). The total length of an UDP payload (set in the IP header) is unchecked. This may lead to various side effects, including Information Leak and Denial-of-Service conditions, depending on a user-defined applications that runs on top of the UDP protocol. (FSMD-2021-0006)

Frequently asked questions

What is CVE-2021-31345?: A vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic R20-11 (All versions < V2303), PLUSCONTROL 1st Gen (All versions). The total length of an UDP payload (set in the IP header) is unchecked. This may lead to various side effects, including Information Leak and Denial-of-Service conditions, depending on a user-defined applications that runs on top of the UDP protocol. (FSMD-2021-0006)
How severe is CVE-2021-31345?: CVE-2021-31345 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2021-31345 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-31345?: CVE-2021-31345 primarily affects Siemens Capital Vstar. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-31345?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-31345 published?: CVE-2021-31345 was published on 2021-11-09 and last updated on 2026-06-17.

References

Affected products (10)

cpe:2.3:a:siemens:capital_vstar:*:*:*:*:*:*:*:*
cpe:2.3:a:siemens:nucleus_net:*:*:*:*:*:*:*:*
cpe:2.3:a:siemens:nucleus_readystart_v3:*:*:*:*:*:*:*:*
cpe:2.3:a:siemens:nucleus_source_code:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:apogee_modular_building_controller_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:apogee_modular_equiment_controller_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:apogee_pxc_compact_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:apogee_pxc_modular_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:talon_tc_compact_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:siemens:talon_tc_modular_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Siemens Capital Vstar

CVE-2021-31884 — Critical (CVSS 9.8): A vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All…
CVE-2021-31346 — High (CVSS 8.2): A vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic…
CVE-2021-31890 — High (CVSS 7.5): A vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic…
CVE-2021-31889 — High (CVSS 7.5): A vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic…
CVE-2021-31885 — High (CVSS 7.5): A vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All…
CVE-2021-25664 — High (CVSS 7.5): A vulnerability has been identified in Capital Embedded AR Classic 431-422 (All versions), Capital Embedded AR Classic…

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