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1 vulnerability found for WE1326 Firmware by Zbtlink
CVE-2026-66747 (GCVE-0-2026-66747)
Vulnerability from cvelistv5
Published
2026-08-05 10:50
Modified
2026-08-05 14:20
Severity ?
9.3 (Critical) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
VLAI Severity ?
EPSS score ?
CWE
- CWE-506 - Embedded Malicious Code
Summary
Zbtlink router firmware ships an embedded remote-control implant, ENDLESSDOORS, present in every published build across the product line. It is the open-source ycsunjane/rctl tool built in as an OpenWrt package (librctl.so), started at boot and run as root under the process name kworker to blend in with the kernel's [kworker/*] threads. It opens no listening port; it phones home over cleartext TCP to a hardcoded command-and-control server (command channel 7000, interactive-shell callback 7001) with no authentication and no transport encryption, re-attempting contact roughly every 35 seconds. Its command handler passes any received string to popen() as uid=0, and a reserved rctlbash command returns an interactive root shell. Because the channel is unauthenticated and cleartext, control is not limited to whoever planted it: any party that answers at the C2 address, occupies the network path (DNS or route hijack), or acquires the hardcoded fallback domain obtains unauthenticated remote code execution as root.
References
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Impacted products
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| Zbtlink | CPE2801 Firmware |
Version: 22.10.09 < cpe:2.3:o:zbtlink:cpe2801_firmware:*:*:*:*:*:*:*:* |
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