CVE-2020-25927: The DNS feature in InterNiche NicheStack TCP/IP 4.0.1 is affected by: Out-of-bounds Read

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HIGH 7.5REMOTEDOWNGRADE

CVE-2020-25927 is a high-severity flaw (CVSS 7.5) affecting nichestack tcp\/ip. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The DNS feature in InterNiche NicheStack TCP/IP 4.0.1 is affected by: Out-of-bounds Read. The impact is: a denial of service (remote). The component is: DNS response processing in function: dns_upcall(). The attack vector is: a specific DNS response packet. The code does not check whether the number of queries/responses specified in the DNS packet header corresponds to the query/response data available in the DNS packet.

Why this priority

High severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

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-125
Published	2021-08-18
Last modified	2026-06-17

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

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

Am I affected?

Timeline

2021-08-18 19:15 UTCPublished CVE record published
2026-06-17 03:07 UTCUpdated Record last modified

hcc-embedded nichestack tcp\/ip DOWNGRADE

Affected: 4.0.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.0.1

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 4.0.1 (Debian / Ubuntu)

apt-cache madison nichestack-tcpip sudo apt install nichestack-tcpip=<VERSION_BEFORE_4.0.1> sudo apt-mark hold nichestack-tcpip

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list nichestack-tcpip sudo dnf downgrade nichestack-tcpip-<VERSION_BEFORE_4.0.1> sudo dnf versionlock add nichestack-tcpip

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2020-25927?

nichestack tcp\/ip: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-25927 being exploited?

CVE-2020-25927 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-2020-25927 affect?

CVE-2020-25927 affects nichestack tcp\/ip. Severity is high (CVSS 7.5). The DNS feature in InterNiche NicheStack TCP/IP 4.0.1 is affected by: Out-of-bounds Read. The impact is: a denial of service (remote). The component is: DNS response processing in function: dns_upcall(). The attack vector is: a specific DNS

How urgent is CVE-2020-25927?

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

Related CVEs

CVE-2020-25928 CRITICAL 9.8 DOWNGRADE The DNS feature in InterNiche NicheStack TCP/IP 4.0.1 is affected by: Buffer Overflow
CVE-2020-25926 HIGH 7.5 DOWNGRADE The DNS client in InterNiche NicheStack TCP/IP 4.0.1 is affected by: Insufficient entropy in the DNS transacti

References

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