HOMEVULNERABILITIESCVE-2020-35684
HIGH

CVE-2020-35684

CWE-20Published: August 19, 2021· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official Description

An issue was discovered in HCC Nichestack 3.0. The code that parses TCP packets relies on an unchecked value of the IP payload size (extracted from the IP header) to compute the length of the TCP payload within the TCP checksum computation function. When the IP payload size is set to be smaller than the size of the IP header, the TCP checksum computation function may read out of bounds (a low-impact write-out-of-bounds is also possible).

NVD Source

Technical Analysis

CVE-2020-35684 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

hcc-embedded1 product(s)
nichestack
siemens4 product(s)
sentron 3wl com35 firmwaresentron 3wl com35sentron 3wa com190 firmwaresentron 3wa com190
Source: NVD CPE · 5 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://cert-portal.siemens.com/productcert/pdf/ssa-789208.pdf
ADVISORYhttps://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/
ADVISORYhttps://www.kb.cert.org/vuls/id/608209
ADVISORYhttps://cert-portal.siemens.com/productcert/pdf/ssa-789208.pdf
ADVISORYhttps://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/
ADVISORYhttps://www.kb.cert.org/vuls/id/608209

All References (8)

→
https://cert-portal.siemens.com/productcert/pdf/ssa-789208.pdfMitigation · Third Party Advisory
→
https://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/Mitigation · Third Party Advisory
→
https://www.hcc-embedded.comProduct
→
https://www.kb.cert.org/vuls/id/608209Third Party Advisory · US Government Resource
→
https://cert-portal.siemens.com/productcert/pdf/ssa-789208.pdfMitigation · Third Party Advisory
→
https://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/Mitigation · Third Party Advisory
→
https://www.hcc-embedded.comProduct
→
https://www.kb.cert.org/vuls/id/608209Third Party Advisory · US Government Resource

Quick Facts

CVE IDCVE-2020-35684
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-20
CISA KEVNo
Affected2 vendor(s)
PublishedAug 19, 2021

Related CVEs (CWE-20)

CVE-2004-0840
10.0
CVE-2024-22476
10.0
CVE-2008-1331
10.0
CVE-2021-26622
10.0
CVE-2023-41917
10.0
CVE-2004-1019
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-35684 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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