CVE-2026-31176Public exploitNetwork attack vector

Unauthenticated command execution via unsanitized stun_user

Published Apr 23, 2026 · Updated Apr 23, 2026

OS command injection in ToToLink A3300R firmware 17.0.0cu.557_B20221024 allows remote attackers to execute commands via stun_user. The sub_4100F0 request handler passes stun_user through Uci_Set_Str, where sprintf inserts it into a command later wrapped by CsteSystem and executed with execv. No authentication or user interaction is required, and a crafted request can run attacker-selected operating-system commands on the router.

CVSS severity6.5
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in ToToLink A3300R firmware 17.0.0cu.557_B20221024 allows remote attackers to execute commands via stun_user. The sub_4100F0 request handler passes stun_user through Uci_Set_Str, where sprintf inserts it into a command later wrapped by CsteSystem and executed with execv. No authentication or user interaction is required, and a crafted request can run attacker-selected operating-system commands on the router.

The record

CVE
CVE-2026-31176
Published
Apr 23, 2026
Updated
Apr 23, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-77, T1190, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

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 exploitPublished

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1190Exploit Public-Facing Application
T1059.004Unix Shell

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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