CVE-2021-31401: An issue was discovered in tcp_rcv() in nptcp.c in HCC embedded InterNiche 4.0.1

Q: How do I fix CVE-2021-31401?

nichestack: upgrade to 4.3; sentron 3wl com35 firmware: upgrade to 1.2.0; sentron 3wa com190 firmware: upgrade to 2.0.0. Exact commands for each OS are on this page.

Q: Is CVE-2021-31401 being exploited?

CVE-2021-31401 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-31401 affect?

CVE-2021-31401 affects nichestack, sentron 3wl com35 firmware, sentron 3wa com190 firmware. Severity is high (CVSS 7.5). An issue was discovered in tcp_rcv() in nptcp.c in HCC embedded InterNiche 4.0.1. The TCP header processing code doesn't sanitize the value of the IP total length field (header length + data length). With a crafted IP packet, an integer ove

Q: How urgent is CVE-2021-31401?

Priority 52/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADEUPGRADEUPGRADE

CVE-2021-31401 is a high-severity flaw (CVSS 7.5) affecting nichestack, sentron 3wl com35 firmware, sentron 3wa com190 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in tcp_rcv() in nptcp.c in HCC embedded InterNiche 4.0.1. The TCP header processing code doesn't sanitize the value of the IP total length field (header length + data length). With a crafted IP packet, an integer overflow occurs whenever the value of the IP data length is calculated by subtracting the length of the header from the total length of the IP packet.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.3% (top 17%)
CISA exploited list	No
Weakness	CWE-20
Published	2021-08-19
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: hcc-embedded · siemens

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-08-19 12:15 UTCPublished CVE record published
2026-06-17 03:51 UTCUpdated Record last modified

hcc-embedded nichestack UPGRADE

Affected: < 4.3

Fixed in: 4.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy nichestack || rpm -q nichestack || nichestack --version

2. UPGRADE to 4.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nichestack

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nichestack

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

siemens sentron 3wl com35 firmware UPGRADE

Affected: < 1.2.0

Fixed in: 1.2.0

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

siemens sentron 3wa com190 firmware UPGRADE

Affected: < 2.0.0

Fixed in: 2.0.0

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-31401?

nichestack: upgrade to 4.3; sentron 3wl com35 firmware: upgrade to 1.2.0; sentron 3wa com190 firmware: upgrade to 2.0.0. Exact commands for each OS are on this page.

Is CVE-2021-31401 being exploited?

CVE-2021-31401 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-31401 affect?

CVE-2021-31401 affects nichestack, sentron 3wl com35 firmware, sentron 3wa com190 firmware. Severity is high (CVSS 7.5). An issue was discovered in tcp_rcv() in nptcp.c in HCC embedded InterNiche 4.0.1. The TCP header processing code doesn't sanitize the value of the IP total length field (header length + data length). With a crafted IP packet, an integer ove

How urgent is CVE-2021-31401?

Priority 52/100. High severity; Remotely exploitable, no login, no user action

Software pages

Siemens vulnerabilities

Related CVEs

CVE-2021-36762 HIGH 7.5 UPGRADE An issue was discovered in HCC Embedded InterNiche NicheStack through 4.3
CVE-2021-31400 HIGH 7.5 UPGRADE An issue was discovered in tcp_pulloutofband() in tcp_in.c in HCC embedded InterNiche 4.0.1
CVE-2021-31228 HIGH 7.5 UPGRADE An issue was discovered in HCC embedded InterNiche 4.0.1
CVE-2021-31227 HIGH 7.5 UPGRADE An issue was discovered in HCC embedded InterNiche 4.0.1
CVE-2021-27565 HIGH 7.5 UPGRADE The web server in InterNiche NicheStack through 4.0.1 allows remote attackers to cause a denial of service (in

References

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