security: reject PATH_TO_CLAUDE_CODE_EXECUTABLE with control characters#1185
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ashwin-ant merged 1 commit intoanthropics:mainfrom Apr 6, 2026
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dirname() preserves embedded newlines, so a value like `/usr/bin/claude\n/attacker/path` writes two lines to GITHUB_PATH, injecting an attacker-controlled directory into PATH for all subsequent workflow steps. Validate the input immediately after reading it and throw if it contains any control characters (0x00-0x1f, 0x7f). This is fail-closed rather than silent stripping — a path with control characters is always misconfigured or malicious. Fixes anthropics#1160 Co-Authored-By: Claude Sonnet 4.6 <[email protected]>
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Bumps the github-actions group with 2 updates: [anthropics/claude-code-action](https://github.com/anthropics/claude-code-action) and [actions/upload-artifact](https://github.com/actions/upload-artifact). Updates `anthropics/claude-code-action` from 1.0.88 to 1.0.93 Release notes *Sourced from [anthropics/claude-code-action's releases](https://github.com/anthropics/claude-code-action/releases).* > v1.0.93 > ------- > > **Full Changelog**: <anthropics/claude-code-action@v1...v1.0.93> > > v1.0.92 > ------- > > **Full Changelog**: <anthropics/claude-code-action@v1...v1.0.92> > > v1.0.91 > ------- > > What's Changed > -------------- > > * Use pinned bun binary for post-steps when allowed\_non\_write\_users is set by [`@OctavianGuzu`](https://github.com/OctavianGuzu) in [anthropics/claude-code-action#1190](https://redirect.github.com/anthropics/claude-code-action/pull/1190) > > **Full Changelog**: <anthropics/claude-code-action@v1...v1.0.91> > > v1.0.90 > ------- > > What's Changed > -------------- > > * fix: forward MCP\_TIMEOUT, MCP\_TOOL\_TIMEOUT, MAX\_MCP\_OUTPUT\_TOKENS to action step by [`@qozle`](https://github.com/qozle) in [anthropics/claude-code-action#1162](https://redirect.github.com/anthropics/claude-code-action/pull/1162) > * security: reject PATH\_TO\_CLAUDE\_CODE\_EXECUTABLE with control characters by [`@qozle`](https://github.com/qozle) in [anthropics/claude-code-action#1185](https://redirect.github.com/anthropics/claude-code-action/pull/1185) > > **Full Changelog**: <anthropics/claude-code-action@v1...v1.0.90> > > v1.0.89 > ------- > > What's Changed > -------------- > > * fix: skip token revocation when no token was acquired by [`@Dave-London`](https://github.com/Dave-London) in [anthropics/claude-code-action#918](https://redirect.github.com/anthropics/claude-code-action/pull/918) > * Use env vars for workflow\_run context values in example workflows by [`@ddworken`](https://github.com/ddworken) in [anthropics/claude-code-action#1125](https://redirect.github.com/anthropics/claude-code-action/pull/1125) > * docs: document include/exclude\_comments\_by\_actor inputs by [`@yuribodo`](https://github.com/yuribodo) in [anthropics/claude-code-action#1130](https://redirect.github.com/anthropics/claude-code-action/pull/1130) > * fix: use correct fallback type for reviewData in fetcher by [`@MaxwellCalkin`](https://github.com/MaxwellCalkin) in [anthropics/claude-code-action#1034](https://redirect.github.com/anthropics/claude-code-action/pull/1034) > * Strip OIDC token request env vars from Claude session by [`@chyipin`](https://github.com/chyipin) in [anthropics/claude-code-action#1011](https://redirect.github.com/anthropics/claude-code-action/pull/1011) > * fix: skip retries for non-retryable errors in retryWithBackoff by [`@ei-grad`](https://github.com/ei-grad) in [anthropics/claude-code-action#1082](https://redirect.github.com/anthropics/claude-code-action/pull/1082) > * fix: restore ripgrep execute bits after bun install --production by [`@qozle`](https://github.com/qozle) in [anthropics/claude-code-action#1163](https://redirect.github.com/anthropics/claude-code-action/pull/1163) > * fix: allow # in branch names for PR checkout and base restore by [`@qozle`](https://github.com/qozle) in [anthropics/claude-code-action#1167](https://redirect.github.com/anthropics/claude-code-action/pull/1167) > * fix: prevent hang in restoreConfigFromBase on repos with .gitmodules by [`@qozle`](https://github.com/qozle) in [anthropics/claude-code-action#1166](https://redirect.github.com/anthropics/claude-code-action/pull/1166) > * fix: strip shell comment lines before parsing claude\_args by [`@VoidChecksum`](https://github.com/VoidChecksum) in [anthropics/claude-code-action#1055](https://redirect.github.com/anthropics/claude-code-action/pull/1055) > * fix: snapshot PR's .claude/ to .claude-pr/ before security restore by [`@qozle`](https://github.com/qozle) in [anthropics/claude-code-action#1172](https://redirect.github.com/anthropics/claude-code-action/pull/1172) > * chore: fix prettier formatting by [`@ashwin-ant`](https://github.com/ashwin-ant) in [anthropics/claude-code-action#1171](https://redirect.github.com/anthropics/claude-code-action/pull/1171) > * chore: fix prettier formatting in parse-sdk-options.test.ts by [`@ashwin-ant`](https://github.com/ashwin-ant) in [anthropics/claude-code-action#1176](https://redirect.github.com/anthropics/claude-code-action/pull/1176) > * fix: pin bun runtime config and improve log hygiene by [`@ashwin-ant`](https://github.com/ashwin-ant) in [anthropics/claude-code-action#1174](https://redirect.github.com/anthropics/claude-code-action/pull/1174) > > New Contributors > ---------------- > > * [`@yuribodo`](https://github.com/yuribodo) made their first contribution in [anthropics/claude-code-action#1130](https://redirect.github.com/anthropics/claude-code-action/pull/1130) > * [`@MaxwellCalkin`](https://github.com/MaxwellCalkin) made their first contribution in [anthropics/claude-code-action#1034](https://redirect.github.com/anthropics/claude-code-action/pull/1034) > * [`@chyipin`](https://github.com/chyipin) made their first contribution in [anthropics/claude-code-action#1011](https://redirect.github.com/anthropics/claude-code-action/pull/1011) > * [`@ei-grad`](https://github.com/ei-grad) made their first contribution in [anthropics/claude-code-action#1082](https://redirect.github.com/anthropics/claude-code-action/pull/1082) > * [`@qozle`](https://github.com/qozle) made their first contribution in [anthropics/claude-code-action#1163](https://redirect.github.com/anthropics/claude-code-action/pull/1163) > * [`@VoidChecksum`](https://github.com/VoidChecksum) made their first contribution in [anthropics/claude-code-action#1055](https://redirect.github.com/anthropics/claude-code-action/pull/1055) > > **Full Changelog**: <anthropics/claude-code-action@v1...v1.0.89> Commits * [`b47fd72`](anthropics/claude-code-action@b47fd72) chore: bump Claude Code to 2.1.101 and Agent SDK to 0.2.101 * [`c26cb64`](anthropics/claude-code-action@c26cb64) chore: bump Claude Code to 2.1.100 and Agent SDK to 0.2.98 * [`657fb7c`](anthropics/claude-code-action@657fb7c) chore: bump Claude Code to 2.1.98 and Agent SDK to 0.2.98 * [`2ff1acb`](anthropics/claude-code-action@2ff1acb) chore: bump Claude Code to 2.1.97 and Agent SDK to 0.2.97 * [`b2fdd80`](anthropics/claude-code-action@b2fdd80) Use pinned bun binary for post-steps when allowed\_non\_write\_users is set ([#1190](https://redirect.github.com/anthropics/claude-code-action/issues/1190)) * [`26ddc35`](anthropics/claude-code-action@26ddc35) chore: bump Claude Code to 2.1.96 and Agent SDK to 0.2.96 * [`3983706`](anthropics/claude-code-action@3983706) chore: bump Claude Code to 2.1.94 and Agent SDK to 0.2.94 * [`6cad158`](anthropics/claude-code-action@6cad158) security: reject PATH\_TO\_CLAUDE\_CODE\_EXECUTABLE with control characters ([#1185](https://redirect.github.com/anthropics/claude-code-action/issues/1185)) * [`0f1fe5e`](anthropics/claude-code-action@0f1fe5e) fix: forward MCP\_TIMEOUT, MCP\_TOOL\_TIMEOUT, MAX\_MCP\_OUTPUT\_TOKENS to action s... * [`6e2bd52`](anthropics/claude-code-action@6e2bd52) fix: pin bun runtime config and improve log hygiene ([#1174](https://redirect.github.com/anthropics/claude-code-action/issues/1174)) * Additional commits viewable in [compare view](anthropics/claude-code-action@1eddb33...b47fd72) Updates `actions/upload-artifact` from 7.0.0 to 7.0.1 Release notes *Sourced from [actions/upload-artifact's releases](https://github.com/actions/upload-artifact/releases).* > v7.0.1 > ------ > > What's Changed > -------------- > > * Update the readme with direct upload details by [`@danwkennedy`](https://github.com/danwkennedy) in [actions/upload-artifact#795](https://redirect.github.com/actions/upload-artifact/pull/795) > * Readme: bump all the example versions to v7 by [`@danwkennedy`](https://github.com/danwkennedy) in [actions/upload-artifact#796](https://redirect.github.com/actions/upload-artifact/pull/796) > * Include changes in typespec/ts-http-runtime 0.3.5 by [`@yacaovsnc`](https://github.com/yacaovsnc) in [actions/upload-artifact#797](https://redirect.github.com/actions/upload-artifact/pull/797) > > **Full Changelog**: <actions/upload-artifact@v7...v7.0.1> Commits * [`043fb46`](actions/upload-artifact@043fb46) Merge pull request [#797](https://redirect.github.com/actions/upload-artifact/issues/797) from actions/yacaovsnc/update-dependency * [`634250c`](actions/upload-artifact@634250c) Include changes in typespec/ts-http-runtime 0.3.5 * [`e454baa`](actions/upload-artifact@e454baa) Readme: bump all the example versions to v7 ([#796](https://redirect.github.com/actions/upload-artifact/issues/796)) * [`74fad66`](actions/upload-artifact@74fad66) Update the readme with direct upload details 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Summary
installClaudeCode()inrun.tspassesPATH_TO_CLAUDE_CODE_EXECUTABLEthroughdirname()and writes the result toGITHUB_PATHviaappendFile. Node'sdirname()preserves embedded newlines, so a value like/usr/bin/claude\n/attacker/pathwrites two lines toGITHUB_PATH— injecting an attacker-controlled directory intoPATHfor all subsequent workflow steps.This adds a fail-closed validation: if the path contains any control characters (0x00-0x1f, 0x7f), the action throws immediately before any use of the value. A path with control characters is always misconfigured or malicious, so failing loudly is better than silent stripping (which could produce a valid-looking but wrong path).
Note:
action.ymlhas a similar pattern at line 193-194 forpath_to_bun_executablevia shelldirname+echo >>. Bashdirnamestrips trailing newlines (POSIX behavior), partially mitigating the shell path, but it could be hardened in a follow-up.Test plan
bun run typecheckpassesbun testpasses (664/664)bun run format:checkpassesdirname()preserves embedded newlines:dirname("/usr/bin/claude\n/evil/path")→"/usr/bin/claude\n/evil"Fixes #1160