CVE-2026-56111

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreHIGH confidence

Score 9.1 from GitHub Security Advisory (severity: HIGH) published 2026-06-24. a secondary CVSS source baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Elevated
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 9.1Exploit: NoneExposed: 0

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

Marlin Firmware through 2.1.2.7, fixed in commit 1f255d1, when built with MESH_BED_LEVELING enabled, contains an out-of-bounds write vulnerability in the M421 G-code handler that allows attackers to corrupt firmware memory by supplying out-of-range X and Y grid indices. Attackers can send a single crafted G-code command via USB serial, network interface, or malicious gcode file to write an attacker-controlled 32-bit float value past the z_values array bounds, corrupting adjacent firmware variables and causing denial of service or firmware state corruption.

CVSS v3
9.1
EG Score
9.1(high)
EG Risk
72(Attend)
EG Risk 72/100SSVC: Attend

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
Severity91% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS
42.2%
KEV
Not listed

Published

June 24, 2026

Last Modified

July 14, 2026

Advisory Details (4)

Auto-updated Jun 24, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr, github_commit.
generic

Marlin Firmware 2.1.2.7 Out-of-Bounds Write via M421 G-code Handler | Advisories | VulnCheck

https://www.vulncheck.com/advisories/marlin-firmware-out-of-bounds-write-via-m421-g-code-handler
github_pr

Bound-check I/J indices in M421 (Mesh Bed Leveling)

Fix merged in MarlinFirmware/Marlin PR #28468 on 2026-06-23 — awaiting tagged release

https://github.com/MarlinFirmware/Marlin/pull/28468
generic

[BUG] M421 (Mesh Bed Leveling) accepts out-of-range I/J indices, unlike the ABL and UBL variants · Issue #28467 · MarlinFirmware/Marlin · GitHub

https://github.com/MarlinFirmware/Marlin/issues/28467
github_commit

commit 1f255d16ec2d (MarlinFirmware/Marlin)

Fix landed in MarlinFirmware/Marlin commit 1f255d16ec2d — awaiting tagged release

https://github.com/MarlinFirmware/Marlin/commit/1f255d16ec2d456454fd444494cfb338d62b0fa1

Vendor Advisories for CVE-2026-56111(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 182× 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 185 total refreshes for this CVE.

  1. 2026-07-24 14:18 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 03:20 UTCEG score recompute
  4. 2026-07-22 14:08 UTCEPSS rescore
  5. 2026-07-21 15:25 UTCEPSS rescore
  6. 2026-07-20 17:08 UTCEPSS rescore
  7. 2026-07-19 14:31 UTCEPSS rescore
  8. 2026-07-19 14:31 UTCEPSS rescore
  9. 2026-07-19 02:29 UTCEPSS rescore
  10. 2026-07-18 10:04 UTCEPSS rescore
  11. 2026-07-17 06:32 UTCGHSA enrichment
  12. 2026-07-17 02:42 UTCGHSA enrichment
  13. 2026-07-16 22:44 UTCGHSA enrichment
  14. 2026-07-16 18:55 UTCGHSA enrichment
  15. 2026-07-16 17:03 UTCEPSS rescore
  16. 2026-07-16 15:05 UTCGHSA enrichment
  17. 2026-07-16 11:09 UTCGHSA enrichment
  18. 2026-07-16 07:13 UTCGHSA enrichment
  19. 2026-07-16 03:21 UTCGHSA enrichment
  20. 2026-07-15 23:31 UTCGHSA enrichment
  21. 2026-07-15 19:42 UTCGHSA enrichment
  22. 2026-07-15 16:57 UTCEPSS rescore
  23. 2026-07-15 16:57 UTCEPSS rescore
  24. 2026-07-15 15:52 UTCGHSA enrichment
  25. 2026-07-15 12:01 UTCGHSA enrichment
Show 75 more
  1. 2026-07-15 07:47 UTCGHSA enrichment
  2. 2026-07-15 03:50 UTCGHSA enrichment
  3. 2026-07-15 02:00 UTCEPSS rescore
  4. 2026-07-15 02:00 UTCEPSS rescore
  5. 2026-07-15 00:00 UTCGHSA enrichment
  6. 2026-07-14 20:10 UTCGHSA enrichment
  7. 2026-07-14 16:20 UTCGHSA enrichment
  8. 2026-07-14 12:30 UTCGHSA enrichment
  9. 2026-07-14 08:38 UTCGHSA enrichment
  10. 2026-07-14 04:41 UTCGHSA enrichment
  11. 2026-07-14 00:47 UTCGHSA enrichment
  12. 2026-07-13 22:31 UTCEPSS rescore
  13. 2026-07-13 20:57 UTCGHSA enrichment
  14. 2026-07-13 17:06 UTCGHSA enrichment
  15. 2026-07-13 13:17 UTCGHSA enrichment
  16. 2026-07-13 09:26 UTCGHSA enrichment
  17. 2026-07-13 06:13 UTCEPSS rescore
  18. 2026-07-13 06:13 UTCEPSS rescore
  19. 2026-07-13 05:36 UTCGHSA enrichment
  20. 2026-07-13 01:46 UTCGHSA enrichment
  21. 2026-07-12 21:56 UTCGHSA enrichment
  22. 2026-07-12 18:06 UTCGHSA enrichment
  23. 2026-07-12 14:15 UTCGHSA enrichment
  24. 2026-07-12 10:16 UTCGHSA enrichment
  25. 2026-07-12 06:26 UTCGHSA enrichment
  26. 2026-07-12 05:46 UTCEPSS rescore
  27. 2026-07-12 02:20 UTCGHSA enrichment
  28. 2026-07-11 22:30 UTCGHSA enrichment
  29. 2026-07-11 18:40 UTCGHSA enrichment
  30. 2026-07-11 14:50 UTCGHSA enrichment
  31. 2026-07-11 11:00 UTCGHSA enrichment
  32. 2026-07-11 08:27 UTCEPSS rescore
  33. 2026-07-11 08:27 UTCEPSS rescore
  34. 2026-07-11 07:10 UTCGHSA enrichment
  35. 2026-07-11 03:19 UTCGHSA enrichment
  36. 2026-07-10 23:29 UTCGHSA enrichment
  37. 2026-07-10 19:38 UTCGHSA enrichment
  38. 2026-07-10 15:48 UTCGHSA enrichment
  39. 2026-07-10 11:28 UTCGHSA enrichment
  40. 2026-07-10 07:38 UTCGHSA enrichment
  41. 2026-07-10 03:46 UTCGHSA enrichment
  42. 2026-07-09 23:47 UTCGHSA enrichment
  43. 2026-07-09 19:56 UTCGHSA enrichment
  44. 2026-07-09 19:10 UTCEPSS rescore
  45. 2026-07-09 19:10 UTCEPSS rescore
  46. 2026-07-09 16:06 UTCGHSA enrichment
  47. 2026-07-09 12:06 UTCGHSA enrichment
  48. 2026-07-09 08:16 UTCGHSA enrichment
  49. 2026-07-09 04:27 UTCGHSA enrichment
  50. 2026-07-09 00:36 UTCGHSA enrichment
  51. 2026-07-08 20:47 UTCGHSA enrichment
  52. 2026-07-08 16:55 UTCGHSA enrichment
  53. 2026-07-08 15:16 UTCEPSS rescore
  54. 2026-07-08 15:16 UTCEPSS rescore
  55. 2026-07-08 13:06 UTCGHSA enrichment
  56. 2026-07-08 09:16 UTCGHSA enrichment
  57. 2026-07-08 05:27 UTCGHSA enrichment
  58. 2026-07-08 01:33 UTCGHSA enrichment
  59. 2026-07-07 21:44 UTCGHSA enrichment
  60. 2026-07-07 17:55 UTCGHSA enrichment
  61. 2026-07-07 13:52 UTCGHSA enrichment
  62. 2026-07-07 13:46 UTCEPSS rescore
  63. 2026-07-07 13:46 UTCEPSS rescore
  64. 2026-07-07 10:02 UTCGHSA enrichment
  65. 2026-07-07 06:11 UTCGHSA enrichment
  66. 2026-07-07 02:19 UTCGHSA enrichment
  67. 2026-07-06 22:19 UTCGHSA enrichment
  68. 2026-07-06 18:24 UTCGHSA enrichment
  69. 2026-07-06 16:27 UTCEPSS rescore
  70. 2026-07-06 16:27 UTCEPSS rescore
  71. 2026-07-06 14:07 UTCGHSA enrichment
  72. 2026-07-06 10:17 UTCGHSA enrichment
  73. 2026-07-06 06:17 UTCGHSA enrichment
  74. 2026-07-06 02:25 UTCGHSA enrichment
  75. 2026-07-06 02:23 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-56111?
CVE-2026-56111 is a critical vulnerability published on June 24, 2026. Marlin Firmware through 2.1.2.7, fixed in commit 1f255d1, when built with MESHBEDLEVELING enabled, contains an out-of-bounds write vulnerability in the M421 G-code handler that allows attackers to corrupt firmware memory by supplying out-of-range X and Y grid indices. Attackers can send a single…
When was CVE-2026-56111 disclosed?
CVE-2026-56111 was first published in the National Vulnerability Database on June 24, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56111 actively exploited?
CVE-2026-56111 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 42.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-56111?
CVE-2026-56111 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-56111?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56111, 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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