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PatchSiren cyber security CVE debrief

CVE-2026-54555 rtk-ai CVE debrief

CVE-2026-54555 is a high-severity vulnerability in rtk that allows command execution. The vulnerability exists in rtk filters and compresses command outputs before they reach the LLM context. Prior to version 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. This allows a command beginning with an allowed prefix, such as 'git', to hide a second command behind one of these constructs. The rewritten command still contains the hidden command, allowing it to run without user confirmation or denial. The vulnerability is fixed in version 0.42.2.

Vendor
rtk-ai
Product
rtk
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-23
Original CVE updated
2026-06-25
Advisory published
2026-06-23
Advisory updated
2026-06-25

Who should care

Users of rtk versions prior to 0.42.2 should be aware of this vulnerability and take immediate action to upgrade to the patched version. This vulnerability has a high CVSS score of 7.8, indicating a significant risk to affected systems. Security teams and administrators responsible for systems utilizing rtk should prioritize patching to prevent potential command execution attacks.

Technical summary

The vulnerability in rtk allows for command execution due to improper handling of shell constructs in the permission splitter. Specifically, the permission splitter did not conservatively split or reject several shell constructs that Bash treats as command execution boundaries or nested execution. This could allow a command starting with an allowed prefix to hide a second command, which would then execute without proper user confirmation or denial. The issue is addressed in rtk version 0.42.2. The CVSS vector for this vulnerability is CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, indicating a high severity.

Defensive priority

This vulnerability has a high CVSS score of 7.8, indicating a significant risk to affected systems. Immediate action should be taken to upgrade to version 0.42.2 or later to prevent potential command execution attacks.

Recommended defensive actions

  • Upgrade to rtk version 0.42.2 or later to patch the vulnerability.
  • Review and update permission rules to ensure conservative splitting or rejection of shell constructs.
  • Monitor systems for suspicious command execution activity.
  • Implement additional security controls to detect and prevent command execution attacks.
  • Verify that all rtk configurations and scripts are updated and validated.

Evidence notes

The CVE record and NVD detail provide official information about the vulnerability. The source item URL provides additional context from the NVD database. The reference URL from GitHub provides information about the advisory and patch.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-54555 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-54555

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-54555 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-54555

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.