CVE-2026-5101Public exploitNetwork attack vector

Authenticated OS command execution via unsanitized lanIp

Published Mar 29, 2026 · Updated Mar 29, 2026

Command injection in TOTOLINK A3300R 17.0.0cu.557_b20221024 allows remote authenticated users to execute OS commands through lanIp. The setLanCfg handler in /cgi-bin/cstecgi.cgi formats the unvalidated lanIp value into a command passed through CsteSystem to execv(). A valid web-management session is required, and successful exploitation runs attacker-chosen commands with the router service's privileges.

CVSS severity8.8
High
EPSS probability2.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in TOTOLINK A3300R 17.0.0cu.557_b20221024 allows remote authenticated users to execute OS commands through lanIp. The setLanCfg handler in /cgi-bin/cstecgi.cgi formats the unvalidated lanIp value into a command passed through CsteSystem to execv(). A valid web-management session is required, and successful exploitation runs attacker-chosen commands with the router service's privileges.

The record

CVE
CVE-2026-5101
Published
Mar 29, 2026
Updated
Mar 29, 2026
Vendor
TOTOLINK
Product
A3300R
Classifications
CWE-74, CWE-78, CWE-77, T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 29, 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=17.0.0cu.557_b20221024

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

TOTOLINK · A3300Rversion=17.0.0cu.557_b20221024

Published CVSS scores

6.5VulDBAV:N/AC:L/Au:S/C:P/I:P/A:P/E:POC/RL:ND/RC:UR
6.3VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
2.1VulDBCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
6.3VulDBCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component
CWE-78Improper Neutralization of Special Elements used in an OS Command
CWE-77Command Injection
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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