Narrated Al-Abbas ibn Abdul Muttalib: Al-Abbas said to the Messenger of Allah ﷺ: We wish to sweep out Zamzam, but in it there are some of these Jinnan, meaning small snakes; so the Messenger of Allah ﷺ ordered that they should be killed.
Hadith Referenceسنن ابي داود / أبواب السلام / 5251
Hadith Gradingالألبانی:صحيح إن كان ابن سابط سمع من العباس | زبیر علی زئی:ضعيف, إسناده ضعيف, مروان بن معاوية عنعن وفي سماع عبد الرحمٰن بن سابط من عباس نظر, انوار الصحيفه، صفحه نمبر 182
Benefits and Issues: It is permissible to kill snakes and harmful creatures even within the Haram, whether a person is in the state of ihram or not. Some scholars have declared this narration to be authentic.
Source: Sunan Abu Dawood – Commentary by Shaykh Umar Farooq Saeedi, Page: 5251