bytecode optimization

About this tag
Bytecode optimization in mruby, a lightweight Ruby implementation, can introduce security vulnerabilities when aggressive transformations alter instruction semantics. A recent CVE (CVE-2026-1979) highlights a use-after-free bug triggered by faulty JMPNOT-to-JMPIF optimization, which corrupts compiled bytecode and leads to memory corruption during execution. This tag covers discussions around such optimization flaws, their impact on virtual machine stability, and the resulting security implications for systems using mruby. Topics include bytecode manipulation, interpreter safety, and patch analysis for embedded Ruby environments.

  1. CVE-2026-1979: mruby VM Use-After-Free from faulty JMPNOT optimization

    A recently assigned CVE, CVE‑2026‑1979, exposes a use‑after‑free (UAF) in mruby’s virtual machine caused by an over‑aggressive bytecode optimization that converts JMPNOT instructions into JMPIF instructions — a logic error that corrupts compiled bytecode and can lead to memory corruption when...
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    • bytecode optimization embedded systems mruby note: only 4 allowed vulnerability
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