Interpreter crash via unchecked top-level super
Published Jul 6, 2026 · Updated Jul 6, 2026
NULL pointer dereference in mrubyc 3.4.1 and earlier allows attackers to crash the interpreter with crafted MRuby bytecode. The OP_SUPER handler in src/vm.c dereferences vm->callinfo_tail to read own_class without checking whether a top-level super call has a call frame. Exploitation requires an application to execute attacker-controlled .mrb bytecode and can terminate the mrubyc process or disrupt its embedding host application.
Summary
What happened
NULL pointer dereference in mrubyc 3.4.1 and earlier allows attackers to crash the interpreter with crafted MRuby bytecode. The OP_SUPER handler in src/vm.c dereferences vm->callinfo_tail to read own_class without checking whether a top-level super call has a call frame. Exploitation requires an application to execute attacker-controlled .mrb bytecode and can terminate the mrubyc process or disrupt its embedding host application.
The record
- CVE
- CVE-2026-38976
- Published
- Jul 6, 2026
- Updated
- Jul 6, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-476, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 6, 2026CVE publishedPublication date reported by the CVE source.
- Jul 6, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
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Public exploit references
- Top-level super crash reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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