GHSA-cc65-xxvf-f7r9

Scrapy vulnerable to ReDoS via XMLFeedSpider

### Impact The following parts of the Scrapy API were found to be vulnerable to a [ReDoS attack](https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS): - The [`XMLFeedSpider`](https://docs.scrapy.org/en/latest/topics/spiders.html#scrapy.spiders.XMLFeedSpider) class or any subclass that uses the default node iterator: `iternodes`, as well as direct uses of the `scrapy.utils.iterators.xmliter` function. - **Scrapy 2.6.0 to 2.11.0**: The [`open_in_browser`](https://docs.scrapy.org/en/latest/topics/debug.html#scrapy.utils.response.open_in_browser) function for a response without a [base tag](https://www.w3schools.com/tags/tag_base.asp). Handling a malicious response could cause extreme CPU and memory usage during the parsing of its content, due to the use of vulnerable regular expressions for that parsing. ### Patches Upgrade to Scrapy 2.11.1. If you are using Scrapy 1.8 or a lower version, and upgrading to Scrapy 2.11.1 is not an option, you may upgrade to Scrapy 1.8.4 instead. ### Workarounds For `XMLFeedSpider`, switch the node iterator to ``xml`` or ``html``. For `open_in_browser`, before using the function, either manually review the response content to discard a ReDos attack or manually define the base tag to avoid its automatic definition by `open_in_browser` later. ### Acknowledgements This security issue was reported by @nicecatch2000 [through huntr.com](https://huntr.com/bounties/271f94f2-1e05-4616-ac43-41752389e26b/).