CVE-2021-31624Public exploit

Adjacent code execution via unchecked urls buffer copy

Published Oct 29, 2021 · Updated Jul 9, 2026

Buffer overflow in Tenda AC9 firmware allows attackers to execute arbitrary code through a crafted urls parameter. The bin/httpd handler for /goform/saveParentControlInfo passes the unchecked urls value directly to strcpy, allowing an oversized string to corrupt the destination buffer. The factory-enabled component is reachable from a neighboring network; the published proof of concept demonstrates a process crash, while the CVE records arbitrary code execution.

CVSS severity8.8
High
EPSS probability1.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Tenda AC9 firmware allows attackers to execute arbitrary code through a crafted urls parameter. The bin/httpd handler for /goform/saveParentControlInfo passes the unchecked urls value directly to strcpy, allowing an oversized string to corrupt the destination buffer. The factory-enabled component is reachable from a neighboring network; the published proof of concept demonstrates a process crash, while the CVE records arbitrary code execution.

The record

CVE
CVE-2021-31624
Published
Oct 29, 2021
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 29, 2021CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record 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 vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.8NIST NVDAV:A/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.

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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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1210Exploitation of Remote Services

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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