# The Secure Code Review Challenge — Solution #5: Notekeeper (Insecure Deserialization)

**URL:** <https://threatmodelingconnect.discourse.group/t/the-secure-code-review-challenge-solution-5-notekeeper-insecure-deserialization/1272>\
**Category:** General\
**Created:** [September 18, 2026, 7:37pm UTC](https://threatmodelingconnect.discourse.group/t/the-secure-code-review-challenge-solution-5-notekeeper-insecure-deserialization/1272 "2026-09-18T19:37:58Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Mohamed\_AboElKheir](https://sea2.discourse-cdn.com/flex002/user_avatar/threatmodelingconnect.discourse.group/mohamed_aboelkheir/32/179_2.png) [@Mohamed\_AboElKheir](https://threatmodelingconnect.discourse.group/u/Mohamed_AboElKheir)\
**Post date:** [September 18, 2026, 7:37pm UTC](https://threatmodelingconnect.discourse.group/t/the-secure-code-review-challenge-solution-5-notekeeper-insecure-deserialization/1272/1 "2026-09-18T19:37:58Z")

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Hi all, The solution of challenge #5 of the secure code review challenge, and its video walkthrough are both live. Also, challenge #6 is also live.

Video Walkthorugh: [https://youtu.be/r3or6Yig\_t0](https://youtu.be/r3or6Yig_t0)  
Solution #5: [the-secure-code-review-challenge/solutions/005-notekeeper/SOLUTION.md at main · mohamed-osama-aboelkheir/the-secure-code-review-challenge · GitHub](https://github.com/mohamed-osama-aboelkheir/the-secure-code-review-challenge/blob/main/solutions/005-notekeeper/SOLUTION.md)  
Challenge #6: [the-secure-code-review-challenge/challenges/006-filedrop at main · mohamed-osama-aboelkheir/the-secure-code-review-challenge · GitHub](https://github.com/mohamed-osama-aboelkheir/the-secure-code-review-challenge/tree/main/challenges/006-filedrop)  
Repo: [GitHub - mohamed-osama-aboelkheir/the-secure-code-review-challenge: A biweekly secure code review challenge series, full working apps, based on real-world vulnerabilities. · GitHub](https://github.com/mohamed-osama-aboelkheir/the-secure-code-review-challenge)