CVE-2026-54555

HIGHPre-NVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 97% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
7.8
EG Score
7.8(medium)
EPSS
2.9%
KEV
Not listed

Published

June 23, 2026

Last Modified

June 25, 2026

Advisory Details (1)

Auto-updated Jun 24, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Permission-gate bypass in rtk rewrite auto-allow via unsplit shell separators · Advisory · rtk-ai/rtk · GitHub

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

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 23× in last 7d / 69× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-14 18:26 UTCEG score recompute
  2. 2026-07-14 05:39 UTCEG score recompute
  3. 2026-07-13 22:31 UTCEPSS rescore
  4. 2026-07-13 16:54 UTCEG score recompute
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  7. 2026-07-13 03:43 UTCEG score recompute
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  12. 2026-07-11 08:27 UTCEPSS rescore
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  14. 2026-07-11 00:38 UTCEG score recompute
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  17. 2026-07-09 19:10 UTCEPSS rescore
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  19. 2026-07-09 10:04 UTCEG score recompute
  20. 2026-07-08 21:19 UTCEG score recompute
  21. 2026-07-08 15:16 UTCEPSS rescore
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  23. 2026-07-08 08:28 UTCEG score recompute
  24. 2026-07-07 19:43 UTCEG score recompute
  25. 2026-07-07 13:46 UTCEPSS rescore
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  1. 2026-07-07 13:46 UTCEPSS rescore
  2. 2026-07-07 06:56 UTCEG score recompute
  3. 2026-07-06 17:44 UTCEG score recompute
  4. 2026-07-06 16:27 UTCEPSS rescore
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  6. 2026-07-06 04:56 UTCEG score recompute
  7. 2026-07-06 02:23 UTCEPSS rescore
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  9. 2026-07-05 16:01 UTCEG score recompute
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  11. 2026-07-05 02:31 UTCEPSS rescore
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  13. 2026-07-04 14:28 UTCEG score recompute
  14. 2026-07-04 06:31 UTCEPSS rescore
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  16. 2026-07-04 01:43 UTCEG score recompute
  17. 2026-07-03 12:58 UTCEG score recompute
  18. 2026-07-03 00:13 UTCEG score recompute
  19. 2026-07-02 11:27 UTCEG score recompute
  20. 2026-07-01 22:41 UTCEG score recompute
  21. 2026-07-01 09:56 UTCEG score recompute
  22. 2026-06-30 23:22 UTCEPSS rescore
  23. 2026-06-30 21:11 UTCEG score recompute
  24. 2026-06-30 08:22 UTCEG score recompute
  25. 2026-06-29 19:37 UTCEG score recompute
  26. 2026-06-29 14:06 UTCEPSS rescore
  27. 2026-06-29 14:06 UTCEPSS rescore
  28. 2026-06-29 06:52 UTCEG score recompute
  29. 2026-06-28 18:07 UTCEG score recompute
  30. 2026-06-28 14:07 UTCEPSS rescore
  31. 2026-06-28 05:18 UTCEG score recompute
  32. 2026-06-28 04:56 UTCEPSS rescore
  33. 2026-06-28 04:56 UTCEPSS rescore
  34. 2026-06-27 16:33 UTCEG score recompute
  35. 2026-06-27 03:47 UTCEG score recompute
  36. 2026-06-27 03:08 UTCEPSS rescore
  37. 2026-06-26 15:02 UTCEG score recompute
  38. 2026-06-26 02:18 UTCEG score recompute
  39. 2026-06-25 13:49 UTCEPSS rescore
  40. 2026-06-25 13:33 UTCEG score recompute
  41. 2026-06-25 00:47 UTCEG score recompute
  42. 2026-06-24 14:05 UTCEPSS rescore
  43. 2026-06-24 12:02 UTCEG score recompute
  44. 2026-06-24 12:01 UTCNVD updatefirst tracked

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Frequently asked(5)

What is CVE-2026-54555?
CVE-2026-54555 is a high vulnerability published on June 23, 2026. 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…
When was CVE-2026-54555 disclosed?
CVE-2026-54555 was first published in the National Vulnerability Database on June 23, 2026, with the most recent update on June 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54555 actively exploited?
CVE-2026-54555 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-54555?
CVE-2026-54555 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-54555?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54555, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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