CVE-2021-37915

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.0% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-10-28 · updated 2026-06-17

Description

An issue was discovered on the Grandstream HT801 Analog Telephone Adaptor before 1.0.29.8. From the limited configuration shell, it is possible to set the malicious gdb_debug_server variable. As a result, after a reboot, the device downloads and executes malicious scripts from an attacker-defined host.

Affected products

Grandstream Ht801 Firmware: before 1.0.29.8 — fixed in 1.0.29.8

How to fix

Upgrade to a fixed version: Grandstream Ht801 Firmware 1.0.29.8. Check the vendor advisory for mitigations.

References

http://firmware.grandstream.com/BETA/Release_Note_HT80x_1.0.29.8.pdf
http://www.grandstream.com/products/gateways-and-atas/analog-telephone-adaptors/product/ht801
https://www.secforce.com/blog/exploiting-grandstream-ht801-ata-cve-2021-37748-cve-2021-37915/
http://firmware.grandstream.com/BETA/Release_Note_HT80x_1.0.29.8.pdf
http://www.grandstream.com/products/gateways-and-atas/analog-telephone-adaptors/product/ht801
https://www.secforce.com/blog/exploiting-grandstream-ht801-ata-cve-2021-37748-cve-2021-37915/

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