CVE-2026-38973

MEDIUMPre-NVD 4.44.4
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 4.4 from GitHub Security Advisory published 2026-07-07. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 4.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory

Also known asEUVD-2026-41976 (ENISA EUVD) · GHSA-r4w3-7jp7-m9g5 (GitHub Security Advisories)Source: ENISA EUVD

4.4EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 4.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

mrubyc through release3.4.1 was found to contain an out-of-bounds read in builtin missing-method lookup inside mrbc_find_method().

CVSS v3
4.4
EG Score
4.4MEDIUMmedium confidence
EG Risk
20
EG Risk 20/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity44% × 45%
Impact severity (EG Severity): CVSS 4.4 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
5th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (4.4): severity, escalated by confirmed exploitation. This CVE's 4.4 is its impact severity (EG Severity), not escalated.

EG Severity
4.4 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 6, 2026

Last Modified

July 9, 2026

Advisory Details (3)

Auto-updated Jul 9, 2026
Patch available. Sources: github_commit.
Web page

Issues · mrubyc/mrubyc · GitHub

https://github.com/mrubyc/mrubyc/issues/279%2C
GitHub commit Patch Available

commit f83a8b67ca1c (mrubyc/mrubyc)

Patch available: mrubyc/mrubyc release4.0.0 (contains commit f83a8b67ca1c)

https://github.com/mrubyc/mrubyc/commit/f83a8b67ca1c7c62ac0dd548a363d79f767c4e30
Web page

GitHub - mrubyc/mrubyc: mruby/c is another implementation of mruby. · GitHub

https://github.com/mrubyc/mrubyc

Vendor Advisories for CVE-2026-38973(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 8× in last 7d / 36× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 99 of 204 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 105 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  2. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  3. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  4. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  5. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  6. 2026-10-25 14:32 UTCEG score recompute
  7. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  8. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  9. 2026-10-23 02:53 UTCEG score recompute
  10. 2026-10-23 02:53 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  11. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  12. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  13. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  14. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  15. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  16. 2026-10-18 03:44 UTCEG score recompute
  17. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  18. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  19. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  20. 2026-10-13 13:54 UTCOSV refresh
  21. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  22. 2026-10-12 16:10 UTCEG score recompute
  23. 2026-10-11 19:52 UTCEG score recompute
  24. 2026-10-11 17:06 UTCEG score recompute
  25. 2026-10-11 14:32 UTCEG score recompute
Show 74 more
  1. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  2. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  3. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  4. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  5. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  6. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  7. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  8. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  9. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  10. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  11. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  12. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  13. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  14. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  15. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.2% · 4th percentile
  16. 2026-09-23 06:27 UTCEG score recompute
  17. 2026-09-23 06:27 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  18. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  19. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  20. 2026-09-18 06:06 UTCEG score recompute
  21. 2026-09-18 06:06 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  22. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  23. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  24. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  25. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  26. 2026-09-14 11:41 UTCEG score recompute
  27. 2026-09-14 11:41 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  28. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  29. 2026-09-13 12:28 UTCEG score recompute
  30. 2026-09-13 12:28 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  31. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  32. 2026-09-12 13:42 UTCEG score recompute
  33. 2026-09-12 13:42 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  34. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  35. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  36. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  37. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  38. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  39. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  40. 2026-09-05 23:15 UTCEG score recompute
  41. 2026-09-05 23:15 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  42. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  43. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  44. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  45. 2026-08-30 08:30 UTCEG score recompute
  46. 2026-08-30 08:30 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  47. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  48. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  49. 2026-08-27 22:02 UTCEG score recompute
  50. 2026-08-27 22:02 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  51. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  52. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  53. 2026-08-26 13:57 UTCEG score recompute
  54. 2026-08-26 13:57 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  55. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  56. 2026-08-25 03:11 UTCEG score recompute
  57. 2026-08-25 03:11 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  58. 2026-08-24 04:26 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  59. 2026-08-23 05:39 UTCEG score recompute
  60. 2026-08-23 05:39 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  61. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  62. 2026-08-22 06:51 UTCEG score recompute
  63. 2026-08-22 06:51 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  64. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  65. 2026-08-21 08:05 UTCEG score recompute
  66. 2026-08-21 08:05 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  67. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  68. 2026-08-20 09:18 UTCEG score recompute
  69. 2026-08-20 09:18 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  70. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  71. 2026-08-19 10:25 UTCEG score recompute
  72. 2026-08-19 10:25 UTCGHSA enrichmentGHSA-r4w3-7jp7-m9g5 · GitHub CVSS 4.4
  73. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  74. 2026-08-18 11:39 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-38973?
CVE-2026-38973 is a medium-severity vulnerability; its CVE record was published on July 6, 2026. mrubyc through release3.4.1 was found to contain an out-of-bounds read in builtin missing-method lookup inside mrbcfindmethod().
When was the CVE record for CVE-2026-38973 published?
The CVE record for CVE-2026-38973 was published on July 6, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of July 9, 2026; the record at its source may have been updated since.
Is CVE-2026-38973 actively exploited?
CVE-2026-38973 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (5th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-38973?
CVE-2026-38973 has a CVSS v3.1 base score of 4.4 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-38973?
A fix for CVE-2026-38973 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-38973 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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