CVE-2020-13389Public exploitNetwork attack vector

Code execution via unchecked scheduling parameter copy

Published May 22, 2020 · Updated Aug 4, 2024

Stack buffer overflow in Tenda AC6, AC9, AC15, and AC18 firmware allows attackers to execute arbitrary code via a crafted scheduling POST. httpd passes the schedStartTime and schedEndTime parameters from /goform/openSchedWifi directly to strcpy for a stack-local buffer, allowing the copy to overwrite the function's return address. The published proof of concept sends the request with a password cookie and demonstrates a service crash; the public record does not establish unauthenticated reachability.

CVSS severity9.8
Critical
EPSS probability2.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in Tenda AC6, AC9, AC15, and AC18 firmware allows attackers to execute arbitrary code via a crafted scheduling POST. httpd passes the schedStartTime and schedEndTime parameters from /goform/openSchedWifi directly to strcpy for a stack-local buffer, allowing the copy to overwrite the function's return address. The published proof of concept sends the request with a password cookie and demonstrates a service crash; the public record does not establish unauthenticated reachability.

The record

CVE
CVE-2020-13389
Published
May 22, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1190
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. May 22, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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