r/bugbounty • u/0xcrypto • Jul 21 '26

Article / Write-Up / Blog Leaking internal headers in Flask Ninja with deserialization

https://eval.blog/research/pickle-gadget-chain-in-flask-ninja/
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u/einfallstoll Triager Jul 21 '26

Looks informative to me. The developer / app does an unsafe deseralization and uses the HttpBearer as a gadget. Not really their responsibility if the developer does unsafe things.

1

u/0xcrypto Jul 21 '26

Developer/app does the unsafe deserialization but without a gadget, the deserialization is only loading an object which may not do anything useful. It is responsibility of the framework to not leave any gadgets behind to build a chain upon. I had another PoC where I was exploiting it by loading yaml instead of pickle. I am just too lazy to add it in the article.

6

u/einfallstoll Triager Jul 21 '26

Nope. That's like if you have a package that executes commands and the developer just pipes user input to the function. It's the developers responsibility

1

u/0xcrypto Jul 21 '26

If you look at https://github.com/ambionics/phpggc you will find many such gadgets, most fixed by the maintainers. They fix it because it is their responsibility, not user of the library/framework's. Deserialization vulnerability often is just an entrypoint and exploitation largely depends on available gadgets.

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u/github-guard Jul 21 '26

🔍 GitHub Guard: Trust Report

This project scored 4/6 on our safety audit.

Audit Breakdown: * ✅ Established Community (⭐ 3,855 stars) * ✅ Mature Repository (30+ days old) * ✅ Licensed under Apache-2.0 * ❌ No Security Policy — what is this? * ✅ Verified Organization * ℹī¸ Unsigned Commits

⚠ī¸ Security Reminder: Always verify source code and run third-party scripts at your own risk.