CVE-2026-5996Public exploitNetwork attack vector

Unauthenticated command execution via tty_server formatting

Published Apr 10, 2026 · Updated Apr 10, 2026

OS command injection in TOTOLINK A7100RU 7.4cu.2313_b20191024 allows remote attackers to execute commands via tty_server. The setAdvancedInfoShow handler formats the untrusted value with snprintf into a command passed through Uci_Set_Str to CsteSystem, which invokes execv. No privileges or user interaction are required; a crafted HTTP request can run attacker-selected OS commands on the router.

CVSS severity9.8
Critical
EPSS probability1.82%
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 A7100RU 7.4cu.2313_b20191024 allows remote attackers to execute commands via tty_server. The setAdvancedInfoShow handler formats the untrusted value with snprintf into a command passed through Uci_Set_Str to CsteSystem, which invokes execv. No privileges or user interaction are required; a crafted HTTP request can run attacker-selected OS commands on the router.

The record

CVE
CVE-2026-5996
Published
Apr 10, 2026
Updated
Apr 10, 2026
Vendor
TOTOLINK
Product
A7100RU
Classifications
CWE-77, CWE-78, T1059
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 10, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=7.4cu.2313_b20191024

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TOTOLINK · A7100RUversion=7.4cu.2313_b20191024

Published CVSS scores

8.9VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
10.0VulDBAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8VulDBCVSS: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.

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

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

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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