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Fencer Vulns
high 7.5

CVE-2021-31400 json

An issue was discovered in tcp_pulloutofband() in tcp_in.c in HCC embedded InterNiche 4.0.1.

published 2021-08-19 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-18310

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
0
none known

Summary

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).

Patch / fix

  • hcc-embedded nichestack 4.3

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-21-217-01 updated cvss 7.5

HCC Embedded InterNiche TCP/IP stack, NicheLite (Update B)

  • HCC Embedded InterNiche stack < 4.3 HCC Embedded NicheLite < 4.3
    affected: vendor fix mitsubishielectric.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

1.49% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.