CVE-2021-31226Public exploitNetwork attack vector

Remote code execution via unchecked POST URI copy

Published Aug 19, 2021 · Updated Aug 3, 2024

Heap buffer overflow in HCC Embedded InterNiche before 4.3 allows remote attackers to execute code through a crafted HTTP POST request. The wbs_post() function uses strcpy() to copy an unchecked request URI into the cgifname field of a fixed 0xEC-byte heap allocation, so URIs longer than 52 bytes overwrite adjacent heap data. The HTTP server must be enabled; reliable control-flow hijacking depends on device-specific memory layout and exploit mitigations, while successful exploitation grants remote device control.

CVSS severity9.8
Critical
EPSS probability3.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in HCC Embedded InterNiche before 4.3 allows remote attackers to execute code through a crafted HTTP POST request. The wbs_post() function uses strcpy() to copy an unchecked request URI into the cgifname field of a fixed 0xEC-byte heap allocation, so URIs longer than 52 bytes overwrite adjacent heap data. The HTTP server must be enabled; reliable control-flow hijacking depends on device-specific memory layout and exploit mitigations, while successful exploitation grants remote device control.

The record

CVE
CVE-2021-31226
Published
Aug 19, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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