WeeChat up to 4.9.0 Relay Authentication weechat_strcasecmp timing discrepancy

Summaryinfo

A vulnerability categorized as problematic has been discovered in WeeChat up to 4.9.0. Affected by this vulnerability is the function weechat_strcasecmp of the component Relay Authentication. Such manipulation leads to timing discrepancy. This vulnerability is uniquely identified as CVE-2026-53525. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability was found in WeeChat up to 4.9.0. It has been rated as problematic. Affected by this issue is the function weechat_strcasecmp of the component Relay Authentication. The manipulation with an unknown input leads to a timing discrepancy vulnerability. Using CWE to declare the problem leads to CWE-208. Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not. Impacted is confidentiality. CVE summarizes:

WeeChat (Wee Enhanced Environment for Chat) is a free chat client. In versions 0.3.1 through 4.9.0, the WeeChat relay authentication uses non-constant-time string comparison functions (weechat_strcasecmp and strcmp) to verify password hashes and plaintext passwords. An attacker can exploit timing differences to extract the server-computed hash character by character, then authenticate using the correct hash without knowing the password. Version 4.9.1 fixes the issue.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-53525 since 06/09/2026. The exploitation is known to be difficult. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1592 by the MITRE ATT&CK project.

Upgrading to version 4.9.1 eliminates this vulnerability.

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Productinfo

Type

• Chat Software

Name

• WeeChat

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9.0

Website

• Product: https://github.com/weechat/weechat/

CPE 2.3info

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