Affected: Homebrew: nbdime

> **A note on the referenced files.** This report was submitted through GitHub's private > vulnerability reporting API, which carries no attachments. Every transcript this report leans > on is reproduced **inline above**, verbatim. The file names it mentions (`poc.sh`, `poc.log`, > per-case transcripts, `evidence.md`, `negative-controls.md`, blob-sweep tables) are the local > evidence bundle those inline excerpts were extracted from, with a checksum manifest. I am happy > to send the bundle by any channel you prefer, or to open a private fork — just say which. The > PoC scripts are self-contained and reproduce the result from a clean environment.

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**Affected:** `<= 3.1.62` — all published releases; also `main` @ `4905b4af` **Verified at runtime:** GitPython `3.1.62` with git `2.55.0` **Date:** 2026-09-10 **Reporter:** MAXI8594

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## Threat model

| | | |---|---| | **Attacker** | anyone who can get the application to clone a URL they control. No account, no credential, no privilege in the consuming application. | | **Pre-need** | a repository they host, with `HEAD` pointing at a branch whose name is the payload. A `git push` to a plain git server is enough — no filesystem access to a server is required (`raw/06`). | | **Gets** | the contents of any file the application's process can read, returned in band through the exception. `/etc/passwd` recovered 34 of 34 lines. | | **Real-world likelihood** | **High.** The vulnerable consumer is six lines of ordinary code with n…