CVE-2022-42787: Wiesemann & Theis: Small number space for allocating session id in Com-Server family

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-11-10 · updated 2026-06-17
Weakness: CWE-330

Description

Multiple W&T products of the Comserver Series use a small number space for allocating sessions ids. After login of an user an unathenticated remote attacker can brute force the users session id and get access to his account on the the device. As the user needs to log in for the attack to be successful a user interaction is required.

Affected products

Wut At-Modem-Emulator Firmware: before 1.48 — fixed in 1.48
Wut Com-Server ++ Firmware: before 1.48 — fixed in 1.48
Wut Com-Server 20Ma Firmware: before 1.48 — fixed in 1.48
Wut Com-Server Highspeed 100Basefx Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed 100Baselx Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed 19" 1Port Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed 19" 4Port Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed Compact Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed Industry Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed Isolated Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed Lc Firmware: before 1.48 — fixed in 1.48
Wut Com-Server Highspeed Oem Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed Office 1Port Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed Office 4Port Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed Poe 3X Isolated Firmware: before 1.48 — fixed in 1.48
Wut Com-Server Highspeed Poe Firmware: before 1.76 — fixed in 1.76
Wut Com-Server Highspeed Ul Firmware: before 1.48 — fixed in 1.48

How to fix

Upgrade to a fixed version: Wut At-Modem-Emulator Firmware 1.48; Wut Com-Server ++ Firmware 1.48; Wut Com-Server 20Ma Firmware 1.48; Wut Com-Server Highspeed 100Basefx Firmware 1.76; Wut Com-Server Highspeed 100Baselx Firmware 1.76; Wut Com-Server Highspeed 19" 1Port Firmware 1.76; Wut Com-Server Highspeed 19" 4Port Firmware 1.76; Wut Com-Server Highspeed Compact Firmware 1.76; Wut Com-Server Highspeed Industry Firmware 1.76; Wut Com-Server Highspeed Isolated Firmware 1.76; Wut Com-Server Highspeed Lc Firmware 1.48; Wut Com-Server Highspeed Oem Firmware 1.76. Check the vendor advisory for mitigations.

References

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