CVE-2026-86547

MEDIUMPre-NVD 6.26.2—
EchelonGraph scoreHIGH confidence

Score 6.2 from GitHub Security Advisory published 2026-09-09. a secondary CVSS source baseline 6.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
6.2EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.2Exploit: None knownExposed: 0

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

mrubyc through 4.0.0 contains a null pointer dereference vulnerability in the op_enter() handler in src/vm.c when processing untrusted bytecode. Attackers can craft malicious .mrb bytecode files with OP_ENTER instructions at the top level to crash the embedding application and cause denial of service.

CVSS v3
6.2
EG Score
6.2(high)
EG Risk
28(Track)
EG Risk 28/100SSVC: 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
Severity62% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
7%
KEV
Not listed

Published

September 9, 2026

Last Modified

September 10, 2026

Advisory Details (3)

Auto-updated Sep 9, 2026
No patch confirmed yet.
generic

mrubyc through 4.0.0 NULL Pointer Dereference via OP_ENTER | Advisories | VulnCheck

https://www.vulncheck.com/advisories/mrubyc-through-4.0.0-null-pointer-dereference-via-op-enter
generic

mrubyc/src/vm.c at release4.0.0 · mrubyc/mrubyc · GitHub

https://github.com/mrubyc/mrubyc/blob/release4.0.0/src/vm.c#L1537
generic

mrubyc/src/vm.c at 4261cf5e5ae5579e3110dab98a04b91c7d919429 · mrubyc/mrubyc · GitHub

https://github.com/mrubyc/mrubyc/blob/4261cf5e5ae5579e3110dab98a04b91c7d919429/src/vm.c#L1534

Vendor Advisories for CVE-2026-86547(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 18× in last 7d / 45× 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. 2026-09-24 15:43 UTCEG score recompute
  2. 2026-09-24 15:43 UTCGHSA enrichment
  3. 2026-09-24 14:04 UTCEPSS rescore
  4. 2026-09-23 17:54 UTCEPSS rescore
  5. 2026-09-23 14:12 UTCEG score recompute
  6. 2026-09-23 14:12 UTCGHSA enrichment
  7. 2026-09-22 16:01 UTCEPSS rescore
  8. 2026-09-22 12:41 UTCEG score recompute
  9. 2026-09-22 12:41 UTCGHSA enrichment
  10. 2026-09-21 21:09 UTCEPSS rescore
  11. 2026-09-21 11:11 UTCEG score recompute
  12. 2026-09-21 11:11 UTCGHSA enrichment
  13. 2026-09-20 20:16 UTCEPSS rescore
  14. 2026-09-20 09:41 UTCEG score recompute
  15. 2026-09-20 09:41 UTCGHSA enrichment
  16. 2026-09-19 08:10 UTCEG score recompute
  17. 2026-09-19 08:10 UTCGHSA enrichment
  18. 2026-09-18 19:28 UTCEPSS rescore
  19. 2026-09-18 06:40 UTCGHSA enrichment
  20. 2026-09-17 05:09 UTCEG score recompute
  21. 2026-09-17 05:09 UTCGHSA enrichment
  22. 2026-09-16 14:09 UTCEPSS rescore
  23. 2026-09-16 05:15 UTCEPSS rescore
  24. 2026-09-16 03:39 UTCEG score recompute
  25. 2026-09-16 03:39 UTCGHSA enrichment
Show 20 more
  1. 2026-09-15 03:12 UTCEPSS rescore
  2. 2026-09-15 03:12 UTCEPSS rescore
  3. 2026-09-15 02:08 UTCGHSA enrichment
  4. 2026-09-14 00:36 UTCEG score recompute
  5. 2026-09-14 00:36 UTCGHSA enrichment
  6. 2026-09-12 23:06 UTCEG score recompute
  7. 2026-09-12 23:06 UTCGHSA enrichment
  8. 2026-09-11 21:35 UTCEG score recompute
  9. 2026-09-11 21:35 UTCGHSA enrichment
  10. 2026-09-11 14:53 UTCEPSS rescore
  11. 2026-09-11 14:53 UTCEPSS rescore
  12. 2026-09-10 20:04 UTCGHSA enrichment
  13. 2026-09-10 15:05 UTCGHSA enrichment
  14. 2026-09-09 13:35 UTCEG score recompute
  15. 2026-09-09 13:34 UTCGHSA enrichment
  16. 2026-09-09 12:50 UTCEG score recompute
  17. 2026-09-09 12:50 UTCGHSA enrichment
  18. 2026-09-09 10:24 UTCEG score recompute
  19. 2026-09-09 10:15 UTCEG score recompute
  20. 2026-09-09 10:15 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-86547?
CVE-2026-86547 is a medium vulnerability published on September 9, 2026. mrubyc through 4.0.0 contains a null pointer dereference vulnerability in the openter() handler in src/vm.c when processing untrusted bytecode. Attackers can craft malicious .mrb bytecode files with OPENTER instructions at the top level to crash the embedding application and cause denial of service.
When was CVE-2026-86547 disclosed?
CVE-2026-86547 was first published in the National Vulnerability Database on September 9, 2026, with the most recent update on September 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-86547 actively exploited?
CVE-2026-86547 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 93.0% of all scored CVEs.
What is the CVSS score of CVE-2026-86547?
CVE-2026-86547 has a CVSS v3 base score of 6.2 (NVD).
How do I remediate CVE-2026-86547?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-86547, 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.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-86547

Explore →

Is Your Infrastructure Affected by CVE-2026-86547?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs