lucasrodes whatstk up to 0.8.x Chat Merge chat_merge.py merge_chats incomplete comparison with missing factors

Summaryinfo

A vulnerability categorized as problematic has been discovered in lucasrodes whatstk up to 0.8.x. The impacted element is the function merge_chats of the file whatstk/utils/chat_merge.py of the component Chat Merge. Such manipulation leads to incomplete comparison with missing factors. This vulnerability is uniquely identified as CVE-2026-121564. The attack can be launched remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in lucasrodes whatstk up to 0.8.x. Affected by this issue is the function merge_chats of the file whatstk/utils/chat_merge.py of the component Chat Merge. The manipulation with an unknown input leads to a incomplete comparison with missing factors vulnerability. Using CWE to declare the problem leads to CWE-1023. The product performs a comparison between entities that must consider multiple factors or characteristics of each entity, but the comparison does not include one or more of these factors. Impacted is integrity. CVE summarizes:

Incomplete Comparison with Missing Factors (CWE-1023) in merge_chats() (whatstk/utils/chat_merge.py), reached from BaseChat.merge(), in whatstk from 0.3.0 before 0.9.0 allows a party that supplies the chat exports to cause messages to be absent from the merged output with no indication that anything was removed, because the merge keeps whole the chat whose first message is oldest and appends from the other only the messages that are strictly newer than the last message of the first. Every message of the second chat that falls inside the date range already covered by the first is therefore discarded. The two chats are compared on their date ranges and not on the identity of the individual messages, so a message held by only one of the two exports is dropped whenever its date falls inside the range of the other, and both branches of _merge_two_chats() behave this way. The merged result is returned without a warning and without a count of what was removed. This results in a merged chat that omits messages the inputs contain, in a library whose documented uses include forensic review and the generation of training data.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-121564 since 11/03/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit.

Upgrading to version 0.9.0 eliminates this vulnerability.

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Productinfo

Vendor

• lucasrodes

Name

• whatstk

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8

Website

• Product: https://github.com/lucasrodes/whatstk/

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