CVE-2021-27114Network attack vector

Remote memory corruption via addassignment overflow

Published Apr 14, 2021 · Updated Aug 3, 2024

Stack-based buffer overflow in D-Link DIR-816 A2 1.10 B05 allows remote attackers to overwrite the return address via crafted HTTP fields. The /goform/addassignment handler copies excessively long s_ip and s_mac parameter values into a stack buffer without sufficient bounds, enabling return-address corruption. The request is unauthenticated and network reachable; the record establishes memory corruption but does not document reliable code execution or a specific service outcome.

CVSS severity9.8
Critical
EPSS probability24.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in D-Link DIR-816 A2 1.10 B05 allows remote attackers to overwrite the return address via crafted HTTP fields. The /goform/addassignment handler copies excessively long s_ip and s_mac parameter values into a stack buffer without sufficient bounds, enabling return-address corruption. The request is unauthenticated and network reachable; the record establishes memory corruption but does not document reliable code execution or a specific service outcome.

The record

CVE
CVE-2021-27114
Published
Apr 14, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 14, 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

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

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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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