CVE-2022-25218: Phicomm k2 Firmware

High severity, CVSS 8.1. EPSS: 1% chance of exploitation in the next 30 days.

The use of the RSA algorithm without OAEP, or any other padding scheme, in telnetd_startup, allows an unauthenticated attacker on the local area network to achieve a significant degree of control over the "plaintext" to which an arbitrary blob of ciphertext will be decrypted by OpenSSL's RSA_public_decrypt() function. This weakness allows the attacker to manipulate the various iterations of the telnetd startup state machine and eventually obtain a root shell on the device, by means of an exchange of crafted UDP packets. In all versions but K2 22.5.9.163 and K3C 32.1.15.93 a successful attack also requires the exploitation of a null-byte interaction error (CVE-2022-25219).

Affected products

• Phicomm k2 Firmware: up to and including 22.5.9.163
• Phicomm k2g Firmware: up to and including 22.6.3.20
• Phicomm k2p Firmware: up to and including 20.4.1.7
• Phicomm k3 Firmware: up to and including 21.5.37.246
• Phicomm k3c Firmware: up to and including 32.1.15.93

Published 2022-03-10. Last modified 2026-06-17.