CVE-2026-56306

MEDIUMPre-NVD 6.46.4—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 73% 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
Elevated
6.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.4Exploit: Elevated riskExposed: 0

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

Capgo before 12.128.2 contains a weak parsing vulnerability in the x-limited-key-id header that allows attackers to bypass subkey enforcement by submitting malformed values, zero, or duplicate headers that result in NaN or falsy values. Remote attackers can manipulate the x-limited-key-id header to disable limited key scoping and execute requests using the main API key context instead of restricted subkey permissions.

CVSS v3
6.4
EG Score
6.4(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity64% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
28%
KEV
Not listed

Published

June 22, 2026

Last Modified

June 23, 2026

Advisory Details (2)

Auto-updated Jun 23, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

middlewareKey: x-limited-key-id weak parsing allows silent bypass/disable of subkey enforcement (NaN/0/duplicate header ambiguity) · Advisory · Cap-go/capgo · GitHub

https://github.com/Cap-go/capgo/security/advisories/GHSA-42vv-8j94-24wj
generic

Capgo - Subkey Enforcement Bypass via x-limited-key-id Header Parsing | Advisories | VulnCheck

https://www.vulncheck.com/advisories/capgo-subkey-enforcement-bypass-via-x-limited-key-id-header-parsing

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 36× 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.

Showing the most recent 100 of 115 total refreshes for this CVE.

  1. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-10 09:35 UTCEPSS rescore
  3. 2026-09-08 22:01 UTCEPSS rescore
  4. 2026-09-07 16:01 UTCEPSS rescore
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  9. 2026-09-01 04:40 UTCEPSS rescore
  10. 2026-08-30 20:32 UTCEG score recompute
  11. 2026-08-30 19:17 UTCEPSS rescore
  12. 2026-08-30 01:22 UTCEPSS rescore
  13. 2026-08-28 21:41 UTCEPSS rescore
  14. 2026-08-27 14:25 UTCEPSS rescore
  15. 2026-08-26 14:46 UTCEPSS rescore
  16. 2026-08-25 13:49 UTCEPSS rescore
  17. 2026-08-24 22:13 UTCEG score recompute
  18. 2026-08-23 15:42 UTCEG score recompute
  19. 2026-08-23 00:19 UTCEPSS rescore
  20. 2026-08-22 14:58 UTCEG score recompute
  21. 2026-08-21 23:49 UTCEPSS rescore
  22. 2026-08-21 08:33 UTCEG score recompute
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  24. 2026-08-20 07:50 UTCEG score recompute
  25. 2026-08-19 17:04 UTCEPSS rescore
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  1. 2026-08-19 04:52 UTCEG score recompute
  2. 2026-08-18 13:48 UTCEPSS rescore
  3. 2026-08-17 13:47 UTCEPSS rescore
  4. 2026-08-17 01:33 UTCEG score recompute
  5. 2026-08-16 14:56 UTCEPSS rescore
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  7. 2026-08-16 00:49 UTCEG score recompute
  8. 2026-08-15 01:30 UTCEPSS rescore
  9. 2026-08-13 23:21 UTCEG score recompute
  10. 2026-08-13 22:00 UTCEPSS rescore
  11. 2026-08-12 22:38 UTCEG score recompute
  12. 2026-08-12 13:51 UTCEPSS rescore
  13. 2026-08-11 21:55 UTCEG score recompute
  14. 2026-08-11 00:00 UTCEPSS rescore
  15. 2026-08-09 20:29 UTCEG score recompute
  16. 2026-08-09 13:46 UTCEPSS rescore
  17. 2026-08-08 19:46 UTCEG score recompute
  18. 2026-08-08 16:37 UTCEPSS rescore
  19. 2026-08-07 19:02 UTCEG score recompute
  20. 2026-08-06 18:19 UTCEG score recompute
  21. 2026-08-06 13:47 UTCEPSS rescore
  22. 2026-08-05 19:17 UTCEPSS rescore
  23. 2026-08-04 15:16 UTCEG score recompute
  24. 2026-08-04 15:10 UTCEPSS rescore
  25. 2026-08-04 10:39 UTCEPSS rescore
  26. 2026-08-03 10:36 UTCEPSS rescore
  27. 2026-08-02 05:09 UTCEG score recompute
  28. 2026-08-02 02:27 UTCEPSS rescore
  29. 2026-08-01 04:26 UTCEG score recompute
  30. 2026-08-01 04:16 UTCEPSS rescore
  31. 2026-07-31 03:42 UTCEG score recompute
  32. 2026-07-30 16:28 UTCEPSS rescore
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  34. 2026-07-30 01:30 UTCEPSS rescore
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  36. 2026-07-29 01:21 UTCEG score recompute
  37. 2026-07-28 15:37 UTCEPSS rescore
  38. 2026-07-27 17:57 UTCEG score recompute
  39. 2026-07-26 15:58 UTCEG score recompute
  40. 2026-07-26 14:54 UTCEPSS rescore
  41. 2026-07-25 14:18 UTCEPSS rescore
  42. 2026-07-24 14:18 UTCEPSS rescore
  43. 2026-07-23 14:18 UTCEPSS rescore
  44. 2026-07-23 03:20 UTCEG score recompute
  45. 2026-07-22 14:08 UTCEPSS rescore
  46. 2026-07-21 15:25 UTCEPSS rescore
  47. 2026-07-20 17:08 UTCEPSS rescore
  48. 2026-07-19 14:31 UTCEPSS rescore
  49. 2026-07-19 14:31 UTCEPSS rescore
  50. 2026-07-19 02:29 UTCEPSS rescore
  51. 2026-07-18 10:04 UTCEPSS rescore
  52. 2026-07-16 17:03 UTCEPSS rescore
  53. 2026-07-15 16:57 UTCEPSS rescore
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  55. 2026-07-15 02:00 UTCEPSS rescore
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  57. 2026-07-13 22:31 UTCEPSS rescore
  58. 2026-07-13 06:13 UTCEPSS rescore
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  60. 2026-07-12 05:46 UTCEPSS rescore
  61. 2026-07-11 08:27 UTCEPSS rescore
  62. 2026-07-11 08:27 UTCEPSS rescore
  63. 2026-07-09 19:10 UTCEPSS rescore
  64. 2026-07-09 19:10 UTCEPSS rescore
  65. 2026-07-08 15:16 UTCEPSS rescore
  66. 2026-07-08 15:16 UTCEPSS rescore
  67. 2026-07-07 13:46 UTCEPSS rescore
  68. 2026-07-07 13:46 UTCEPSS rescore
  69. 2026-07-06 16:27 UTCEPSS rescore
  70. 2026-07-06 16:27 UTCEPSS rescore
  71. 2026-07-06 02:23 UTCEPSS rescore
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  73. 2026-07-05 02:31 UTCEPSS rescore
  74. 2026-07-05 02:30 UTCEPSS rescore
  75. 2026-07-04 06:31 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-56306?
CVE-2026-56306 is a medium vulnerability published on June 22, 2026. Capgo before 12.128.2 contains a weak parsing vulnerability in the x-limited-key-id header that allows attackers to bypass subkey enforcement by submitting malformed values, zero, or duplicate headers that result in NaN or falsy values. Remote attackers can manipulate the x-limited-key-id header to…
When was CVE-2026-56306 disclosed?
CVE-2026-56306 was first published in the National Vulnerability Database on June 22, 2026, with the most recent update on June 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56306 actively exploited?
CVE-2026-56306 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 72.4% of all scored CVEs.
What is the CVSS score of CVE-2026-56306?
CVE-2026-56306 has a CVSS v3 base score of 6.4 (NVD).
How do I remediate CVE-2026-56306?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56306, 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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