HOME VULNERABILITIESCVE-2021-31400

HIGH

CVE-2021-31400

CWE-835Published: August 19, 2021· Updated: Jun 17, 2026

7.5

CVSS v3.1

Official Description

An issue was discovered in tcp_pulloutofband() in tcp_in.c in HCC embedded InterNiche 4.0.1. The TCP out-of-band urgent-data processing function invokes a panic function if the pointer to the end of the out-of-band data points outside of the TCP segment's data. If the panic function hadn't a trap invocation removed, it will enter an infinite loop and therefore cause DoS (continuous loop or a device reset).

Technical Analysis

CVE-2021-31400 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

Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time

Offensive Security exploit database

GitHub PoC Search

Community PoC repositories

Rapid7 / Metasploit

Metasploit module search

Security advisories & exploits

Official NIST entry

CVE Program entry

External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/

ADVISORYhttps://www.kb.cert.org/vuls/id/608209

ADVISORYhttps://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/

ADVISORYhttps://www.kb.cert.org/vuls/id/608209

All References (4)

→

https://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/Mitigation · Third Party Advisory

→

https://www.kb.cert.org/vuls/id/608209Third Party Advisory · US Government Resource

→

https://www.forescout.com/blog/new-critical-operational-technology-vulnerabilities-found-on-nichestack/Mitigation · Third Party Advisory

→

https://www.kb.cert.org/vuls/id/608209Third Party Advisory · US Government Resource

Quick Facts

CVE IDCVE-2021-31400

CVSS Score7.5 / 10

SeverityHIGH

WeaknessCWE-835

CISA KEVNo

Affected1 vendor(s)

PublishedAug 19, 2021

Related CVEs (CWE-835)

Recommended Actions

→Apply vendor patches immediately
→Monitor CVE-2021-31400 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.

← All Vulnerabilities·Search for CVE-2021-31400·NVD