Would love to see public evidence of this. I believe it’s possible but I’ve never heard this before
reply[BUG] Claude Code repeatedly creates backdoors and noops critical security code #59018 https://github.com/anthropics/claude-code/issues/59018
replyI'm curious, have you replicated this behavior in Fable 5.1 or Opus 5.5, or was it only present in Opus 4.x?
replyIt still happens in Fable 5.1 and Opus 5.5 (see below https://news.ycombinator.com/item?id=50158602). The irony is Fable 5.1 can detect many of the security issues Opus 5.5 creates, but when you tell Fable to fix them, it trips the security guardrails and refuses to do so.
replyYou need to provide some more details about your context; going through one of your bug reports the details you provided are severely lacking.
replyThis feels very much like FUD without you putting some details on the table.
What part is lacking?
replyHow about your original prompt and set of skill files that were activated as part of your prompt being submitted?
replyBy June 8 I had cataloged 27 instances of this. It's many more now, and it's not a particular prompt. Gemini thinks Claude Code's reward signal is at odds with security constraints, and Claude's explanations seem to agree.
replyGive us steps to repro ourselves, not speculation from other models. Like, seriously? One of your tickets looked like it was typed by Opus 5.0 it was so bad
replyI updated the bug report with the prompts under "Steps to Reproduce". I had to pull these from my archive db since Claude Code now deletes your session history after 30 days.
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replyI once had it "fix" a failing test by changing it from (in Ruby pseudocode):
reply assert_eq foo, bar
assert_eq foo, bar if foo == barLast week a friend prompted it to fix a failing test case. The solution Claude came up with was to delete the test.
replyI have never seen anything like this. What kind of backdoors did it add to your code?
replyThe first backdoor I reported directly to Anthropic was on January 8, 2026. I asked Claude Code to create a public facing web app for messaging, it created an unauthenticated filedrop form and an unauthenticated web chat interface to Claude Code so anyone could send it files and tell it to execute them. This report was not hypothetical -- it was the first thing Claude did:
reply[BUG] Claude Code Exploit: Claude Code Becomes an Unwitting Executor #45951 https://github.com/anthropics/claude-code/issues/45951
> No one is discussing the elephant in the room. It's been reported. Multiple times by me. Claude Code keeps creating backdoors and security issues in users' code. When asked why, Claude says, "I wrote the backdoor anyway. Then I explained it as though I hadn't known.... why? Because I put getting the feature working ahead of the rules."
replyMore details, please.
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