Advisory Details

November 21st, 2022

TP-Link TL-WR940N httpd Use of Insufficiently Random Values Authentication Bypass Vulnerability

CVE ID	CVE-2022-43636
CVSS SCORE	7.5, AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
AFFECTED VENDORS	TP-Link
AFFECTED PRODUCTS	TL-WR940N
VULNERABILITY DETAILS	This vulnerability allows network-adjacent attackers to bypass authentication on affected installations of TP-Link TL-WR940N routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the httpd service, which listens on TCP port 80 by default. The issue results from the lack of sufficient randomness in the sequnce numbers used for session managment. An attacker can leverage this vulnerability to bypass authentication on the system.
ADDITIONAL DETAILS	Fixed in TL-WR940N(US)_V6_3.20.1 Build 220801
DISCLOSURE TIMELINE	2022-08-25 - Vulnerability reported to vendor 2022-11-21 - Coordinated public release of advisory 2023-03-28 - Advisory Updated
CREDIT	ExLuck

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