CVE-2026-5818

HIGHPre-NVD 7.27.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 95% 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
7.2
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.2Exploit: NoneExposed: 0

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

Incorrect check of function return value in Caliptra Core Runtime Firmware (ActivateFirmwareCmd::activate_fw modules) allows bypass of Caliptra Core's verification of the MCU FW during a hitless update.

This issue affects Core Runtime Firmware: from 2.0.0 through 2.0.1, 2.1.0.

CVSS v3
7.2
EG Score
7.2(medium)
EPSS
5.1%
KEV
Not listed

Published

June 24, 2026

Last Modified

June 25, 2026

Advisory Details (1)

Auto-updated Jun 24, 2026
Patch available. Sources: github.
github Patch Available

MCU Firmware Update Authentication Bypass on Caliptra Core · Advisory · chipsalliance/caliptra-sw · GitHub

https://github.com/chipsalliance/caliptra-sw/security/advisories/GHSA-456r-gcjr-6rxq

Data Freshness Timeline

(refreshed 0× in last 7d / 0× 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. 2026-07-11 14:35 UTCEG score recompute
  2. 2026-07-11 08:27 UTCEPSS rescore
  3. 2026-07-11 08:27 UTCEPSS rescore
  4. 2026-07-11 03:11 UTCEG score recompute
  5. 2026-07-10 15:49 UTCEG score recompute
  6. 2026-07-10 04:26 UTCEG score recompute
  7. 2026-07-09 19:10 UTCEPSS rescore
  8. 2026-07-09 19:10 UTCEPSS rescore
  9. 2026-07-09 16:58 UTCEG score recompute
  10. 2026-07-09 05:38 UTCEG score recompute
  11. 2026-07-08 18:18 UTCEG score recompute
  12. 2026-07-08 15:16 UTCEPSS rescore
  13. 2026-07-08 15:16 UTCEPSS rescore
  14. 2026-07-08 06:58 UTCEG score recompute
  15. 2026-07-07 19:38 UTCEG score recompute
  16. 2026-07-07 13:46 UTCEPSS rescore
  17. 2026-07-07 13:46 UTCEPSS rescore
  18. 2026-07-07 08:14 UTCEG score recompute
  19. 2026-07-06 20:52 UTCEG score recompute
  20. 2026-07-06 16:27 UTCEPSS rescore
  21. 2026-07-06 16:27 UTCEPSS rescore
  22. 2026-07-06 09:29 UTCEG score recompute
  23. 2026-07-06 02:23 UTCEPSS rescore
  24. 2026-07-06 02:23 UTCEPSS rescore
  25. 2026-07-05 22:09 UTCEG score recompute
Show 38 more
  1. 2026-07-05 10:49 UTCEG score recompute
  2. 2026-07-05 02:31 UTCEPSS rescore
  3. 2026-07-05 02:30 UTCEPSS rescore
  4. 2026-07-04 23:29 UTCEG score recompute
  5. 2026-07-04 12:09 UTCEG score recompute
  6. 2026-07-04 06:31 UTCEPSS rescore
  7. 2026-07-04 06:31 UTCEPSS rescore
  8. 2026-07-04 00:46 UTCEG score recompute
  9. 2026-07-03 13:18 UTCEG score recompute
  10. 2026-07-03 01:58 UTCEG score recompute
  11. 2026-07-02 14:38 UTCEG score recompute
  12. 2026-07-02 03:18 UTCEG score recompute
  13. 2026-07-01 15:58 UTCEG score recompute
  14. 2026-07-01 15:07 UTCEPSS rescore
  15. 2026-07-01 04:38 UTCEG score recompute
  16. 2026-06-30 23:22 UTCEPSS rescore
  17. 2026-06-30 17:16 UTCEG score recompute
  18. 2026-06-30 05:48 UTCEG score recompute
  19. 2026-06-29 18:28 UTCEG score recompute
  20. 2026-06-29 14:06 UTCEPSS rescore
  21. 2026-06-29 07:07 UTCEG score recompute
  22. 2026-06-28 19:44 UTCEG score recompute
  23. 2026-06-28 14:07 UTCEPSS rescore
  24. 2026-06-28 08:24 UTCEG score recompute
  25. 2026-06-28 04:56 UTCEPSS rescore
  26. 2026-06-27 21:04 UTCEG score recompute
  27. 2026-06-27 09:44 UTCEG score recompute
  28. 2026-06-27 03:08 UTCEPSS rescore
  29. 2026-06-26 22:24 UTCEG score recompute
  30. 2026-06-26 11:04 UTCEG score recompute
  31. 2026-06-25 22:56 UTCEG score recompute
  32. 2026-06-25 13:50 UTCEPSS rescore
  33. 2026-06-25 11:35 UTCEG score recompute
  34. 2026-06-25 00:13 UTCEG score recompute
  35. 2026-06-24 14:05 UTCEPSS rescore
  36. 2026-06-24 12:53 UTCEG score recompute
  37. 2026-06-24 01:30 UTCEG score recompute
  38. 2026-06-24 01:29 UTCNVD updatefirst tracked

Frequently asked(5)

What is CVE-2026-5818?
CVE-2026-5818 is a high vulnerability published on June 24, 2026. Incorrect check of function return value in Caliptra Core Runtime Firmware (ActivateFirmwareCmd::activate_fw modules) allows bypass of Caliptra Core's verification of the MCU FW during a hitless update. This issue affects Core Runtime Firmware: from 2.0.0 through 2.0.1, 2.1.0.
When was CVE-2026-5818 disclosed?
CVE-2026-5818 was first published in the National Vulnerability Database on June 24, 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-2026-5818 actively exploited?
CVE-2026-5818 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 5.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-5818?
CVE-2026-5818 has a CVSS v3 base score of 7.2 (NVD).
How do I remediate CVE-2026-5818?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-5818, 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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