AI Developer Uncovers Cache Bugs in Claude Code

A developer has identified two cache bugs in the standalone installation of Claude Code, according to PANews. The discovery was made through reverse engineering using Ghidra, MITM proxy, and radare2 on the 228MB binary file. These bugs could potentially increase API costs by 10-20 times without user awareness. The analysis has been submitted to GitHub (issue #40524) and has been marked by Anthropic as a regression bug for resolution. The first bug is found in the custom Bun runtime used by the standalone version, where an error in the billing identifier replacement logic causes a complete cache rebuild with each request. The second bug affects users who utilize the --resume or --continue options to restore sessions. Introduced in version 2.1.69, this bug results in a cache prefix mismatch, leading to the entire conversation history being rewritten instead of being read from the cache. Anthropic engineers have previously confirmed that users are reaching usage limits much faster than anticipated.