CVE-2021-41125
MEDIUMScrapy HTTP authentication credentials potentially leaked to target websites
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
scrapy🐍scrapyReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Scrapy is a high-level web crawling and scraping framework for Python. If you use HttpAuthMiddleware (i.e. the http_user and http_pass spider attributes) for HTTP authentication, all requests will expose your credentials to the request target. This includes requests generated by Scrapy components, such as robots.txt requests sent by Scrapy when the ROBOTSTXT_OBEY setting is set to True, or as requests reached through redirects. Upgrade to Scrapy 2.5.1 and use the new http_auth_domain spider attribute to control which domains are allowed to receive the configured HTTP authentication credentials. If you are using Scrapy 1.8 or a lower version, and upgrading to Scrapy 2.5.1 is not an option, you may upgrade to Scrapy 1.8.1 instead. If you cannot upgrade, set your HTTP authentication credentials on a per-request basis, using for example the w3lib.http.basic_auth_header function to convert your credentials into a value that you can assign to the Authorization header of your request, instead of defining your credentials globally using HttpAuthMiddleware.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | scrapy | all versions | 1.8.1 |
| 🐍PyPI | scrapy | ≥ 2.0.0&&< 2.5.1 | 2.5.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for scrapy. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update scrapy to 1.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41125 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2021-41125 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2021-41125. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2021-41125 in your dependencies?
O3 detects CVE-2021-41125 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.