fix: prevent command injection in auto-stage.js#9
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cincyjosh wants to merge 1 commit intokaranb192:mainfrom
Open
fix: prevent command injection in auto-stage.js#9cincyjosh wants to merge 1 commit intokaranb192:mainfrom
cincyjosh wants to merge 1 commit intokaranb192:mainfrom
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stageFile() was building a shell command with an unescaped filename:
execSync(`git add "${filePath}"`)
A filename containing `"` followed by shell metacharacters (e.g. `;`,
`&&`, `|`) would break out of the quotes and execute arbitrary commands
when Claude Code's PostToolUse hook ran.
Replace execSync with spawnSync using an args array, which bypasses the
shell entirely so the filename is always treated as a literal argument.
Add `--` so git cannot interpret filenames beginning with `-` as flags.
Adds a regression test that creates a file whose name embeds a `touch`
command and asserts the marker file is not created after stageFile runs.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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Summary
stageFile()inauto-stage.jsbuilt a shell command using template string interpolation —execSync(\git add "${filePath}"`). A filename containing"followed by shell metacharacters (e.g.evil"; touch marker; echo "x.txt`) breaks out of the quotes and executes arbitrary commands when the PostToolUse hook fires.execSyncwithspawnSync('git', ['add', '--', filePath], ...), which passes the filename as a literal argument without involving a shell. The--prevents git from interpreting filenames that begin with-as flags.touchcommand and asserts the marker file is not created afterstageFileruns.Security context
This was identified during a code audit. The attack requires either:
Both are realistic in adversarial or misconfigured environments. The fix has zero functional impact on normal usage.
Test plan
npm test)execSyncthe new test fails (marker file is created); withspawnSyncit passes🤖 Generated with Claude Code