Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Local vector because exploit requires supplying a crafted file; no privileges needed to craft the file; availability-only impact from process crash.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
Null pointer dereference in mrubyc through 4.0.0 allows an attacker who can supply untrusted .mrb bytecode to crash any application embedding the VM. The op_enter() handler in src/vm.c fails to validate execution context before dereferencing, and OP_ENTER instructions placed at the top level of a crafted bytecode file - where no call frame exists - trigger the dereference and terminate the embedding application. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The target application must accept and execute .mrb bytecode supplied by or influenced by the attacker - for example, through a file upload interface, a network-facing script endpoint, or an over-the-air update channel that does not validate bytecode integrity. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 base score of 6.2 (AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) accurately reflects the impact profile: availability-only, no confidentiality or integrity impact, and a local attack vector that requires the attacker to supply the malicious bytecode to the application. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | No vendor-released patched version is identified from the available reference data. … Detailed patch versions, workarounds, and compensating controls in full report. |
Threat intelligence, references, and detailed analysis are available after sign-in.
Same weakness CWE-476 – NULL Pointer Dereference
View allSame technique Denial Of Service
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-74787
GHSA-42q4-rvcw-q7wc