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LowPublic exploit

Command Injection in Totolink A3300R setVpnPassCfg via pptpPassThru

IdentifiersCVE-2026-5105CWE-77· Improper Neutralization of Special…

CVE-2026-5105 is a remote command injection vulnerability affecting Totolink A3300R firmware version 17.0.0cu.557_b20221024. The flaw is in the Parameter Handler component, specifically the setVpnPassCfg function exposed through /cgi-bin/cstecgi.cgi. According to the provided content, improper handling of the pptpPassThru argument allows attacker-controlled input to be interpreted as operating system commands. Public reporting and detection content indicate the issue can be triggered over HTTP by supplying a crafted value to the pptpPassThru parameter, including command-substitution payloads such as a sleep-based timing probe.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows remote execution of arbitrary OS commands in the context of the vulnerable web application or underlying device service. This can enable compromise of the router, modification of configuration, execution of follow-on payloads, disruption of device operation, and potentially full loss of confidentiality, integrity, and availability on the affected device. The provided content notes that public exploit information exists, increasing the likelihood of opportunistic exploitation.

Mitigation

If you can’t patch tonight, do this now.

Restrict access to the router management interface and /cgi-bin/cstecgi.cgi to trusted administrative networks only. Disable remote administration from untrusted networks, enforce network segmentation, and place management services behind VPN or ACL controls. Monitor for suspicious requests targeting pptpPassThru, especially payloads containing shell metacharacters or timing-based probes such as sleep commands. If feasible, use WAF or reverse-proxy filtering to block command-injection patterns until a vendor fix is applied.

Remediation

Patch, then assume compromise.

Upgrade Totolink A3300R firmware to a vendor-fixed release if one is available. If no patched firmware is currently available in the provided information, remediation should include obtaining vendor guidance and replacing or retiring affected firmware version 17.0.0cu.557_b20221024. The vulnerable handling of the pptpPassThru parameter in setVpnPassCfg within /cgi-bin/cstecgi.cgi must be corrected so that user input is not passed to shell execution contexts.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
TotolinkA3300r Firmwareoperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

5 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

5 SOURCESView more in app
What this page doesn’t show

The version that knows your environment.

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2026-5105
NVD
nvd.nist.gov/vuln/detail/CVE-2026-5105
MITRE CWE · CWE-77
Improper Neutralization of Special Elements…
Third Party Advisory
github.com/LvHongW/Vuln-of-totolink_A3300R/tree/main/A3300R_pptpPassThru_cmd_inject
Third Party Advisory
vuldb.com/vuln/354130
Third Party Advisory
vuldb.com/vuln/354130/cti
Permissions Required
vuldb.com/submit/779143
Product
totolink.net