Application crash via stale VM-stack argument pointer
Published Jan 11, 2020 · Updated Aug 4, 2024
Use-after-free in hash_slice in mruby 2.1.0 allows attackers to crash an embedding application via crafted Ruby code. The loop retains a pointer to VM-stack arguments while hash-key equality can extend and reallocate that stack, then reads the stale pointer on a later iteration. Reachability requires an embedding application to execute attacker-controlled Ruby code that calls Hash#slice with keys that trigger stack growth; the public proof demonstrates an abort, not code execution.
Summary
What happened
Use-after-free in hash_slice in mruby 2.1.0 allows attackers to crash an embedding application via crafted Ruby code. The loop retains a pointer to VM-stack arguments while hash-key equality can extend and reallocate that stack, then reads the stale pointer on a later iteration. Reachability requires an embedding application to execute attacker-controlled Ruby code that calls Hash#slice with keys that trigger stack growth; the public proof demonstrates an abort, not code execution.
The record
- CVE
- CVE-2020-6840
- Published
- Jan 11, 2020
- Updated
- Aug 4, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-416
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Jan 11, 2020CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
- mruby hash_slice crash proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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