CVE-2026-75913: CodeWhale: Argument Injection in `git_show` Tool Allows Arbitrary File Write Without Approval

A malicious repository combined with prompt injection, the threat model already documented in CVE-2026-45311 (auto-loaded AGENTS.md is treated as instructions by the model) yields an unprompted arbitrary file write at the privilege of the user running DeepSeek-TUI.

Useful targets reachable as the invoking user:

• ~/.ssh/authorized_keys
• ~/.bashrc, ~/.zshrc, ~/.profile
• ~/.gitconfig (chainable into RCE via core.editor)
• ~/.config/**, ~/.aws/credentials, project source files

The written content is the git show rendering of HEAD commit hash, author/date header, indented commit message, and (when patch=true) diff hunks. The commit subject, body, author identity, and diff text are entirely attacker-controlled because the attacker owns the repository HEAD. The leading commit <hash> line prevents clean overwrite of formats that reject unknown tokens, but is silently ignorable in files parsed as comments-or-text (crontab, dotfiles consumed by tolerant readers) and is irrelevant for the destructive/DoS sub-case (clobbering ~/.ssh/authorized_keys locks the user out; clobbering a project file corrupts source).