No exploitation reportedFix available

CVE-2020-28388

Q: Is CVE-2020-28388 actively exploited?

Active exploitation of CVE-2020-28388 has not been confirmed. Its EPSS score was 1.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2020-28388?

CVE-2020-28388 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

No exploitation reported by the sources we read.

Published2021-02-09
WeaknessCWE-342

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A vulnerability has been identified in APOGEE PXC Compact (BACnet) (All versions < V3.5.5), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.20), APOGEE PXC Modular (BACnet) (All versions < V3.5.5), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.20), Nucleus NET (All versions < V5.2), Nucleus ReadyStart V3 (All versions < V2012.12), Nucleus Source Code (All versions), PLUSCONTROL 1st Gen (All versions), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). Initial Sequence Numbers (ISNs) for TCP connections are derived from an insufficiently random source. As a result, the ISN of current and future TCP connections could be predictable. An attacker could hijack existing sessions or spoof future ones.

Timeline

dates in UTC

2021-02-0918:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-28388?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-28388?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Siemens capital vstar

Branch	Affected	Fixed in	Source
—	all versions	no fix published	NVD

Siemens nucleus net

Branch	Affected	Fixed in	Source
5.2	< 5.2	5.2	NVD

Siemens nucleus readystartversion to verify

Branch	Affected	Fixed in	Source
2012.12	< 2012.12	2012.12	NVD

2 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

ICSA-22-349-16 CISA6 known affected
Siemens APOGEE and TALON
APOGEE PXC Compact (BACnet) · APOGEE PXC Compact (P2 Ethernet) · APOGEE PXC Modular (BACnet) · +3 more
ICSA-21-068-08 CISA1 known affected
Siemens Energy PLUSCONTROL 1st Gen
Siemens PLUSCONTROL 1st Gen: All versions

Full record on NVD

Fix

Vendor fix CISA ICSA-22-349-16 · 2 productsUpdate to V2.8.20 or later version
Vendor fix CISA ICSA-22-349-16 · 4 productsUpdate to V3.5.5 or later version
Mitigation from the vendor CISA ICSA-21-068-08 · 1 productPLUSCONTROL devices are typically located in a separate LAN segment of energy transmission solutions, where an attacker could use this vulnerability to disrupt SER messages or Trace functionalities. Therefore, review the status of the defense in depth recommendations that apply to your specific dep…

Advisories and patches

cert-portal.siemens.comVendor Advisory
cert-portal.siemens.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2026-06-02
OpenCVESSVC decisionnone—
CNACVSS 3.16.5read 2026-10-23
NVDCVSS 3.15.3read 2026-10-23
NVDCVSS 2.05read 2026-10-23
CNAweakness (CWE)CWE-342read 2026-10-23
FIRST EPSSEPSS score1.4 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Published: 2021-02-09
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2020-28388?

Is CVE-2020-28388 actively exploited?

Active exploitation of CVE-2020-28388 has not been confirmed. Its EPSS score was 1.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-28388?

CVE-2020-28388 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

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