In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
Priority MEDIUM 45CWE-416Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-416 and the CVSS impact.
Summary
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
Why it matters now
EPSS 0.01505 74th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2020-6840
- 2026-10-03 Alias added: GHSA-4v2f-5xhv-8ff4
References
More Mruby vulnerabilities
- TI-2022-00033 Heap-based Buffer Overflow in mruby/mruby CVSS 3.1CRITICAL 9.8
- TI-2026-01636 mruby JMPNOT-to-JMPIF Optimization vm.c mrb_vm_exec use after free CVSS 4.0MEDIUM 4.8
- TI-2025-11794 mruby array.c ary_fill_exec out-of-bounds write CVSS 4.0MEDIUM 4.8
- TI-2025-06567 mruby nregs codegen.c scope_new heap-based overflow CVSS 4.0MEDIUM 4.8
- TI-2018-07224 In versions of mruby up to and including 1.4.0, an integer overflow exists in… CVSS 3.1CRITICAL 9.8
- TI-2022-01100 Use-After-Free in str_escape in mruby/mruby in mruby/mruby CVSS 3.1CRITICAL 9.8
Sources
- CVE-2020-6840 · CVE Program
- CVE-2020-6840 · NVD
- FIRST EPSS
- GHSA-4v2f-5xhv-8ff4 · GitHub Advisory Database · CC BY 4.0
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