Process crash via stale mjs_apply buffer pointer
Published Jan 27, 2022 · Updated Aug 4, 2024
Heap use-after-free in mjs_apply in Cesanta mJS 2.20.0 allows local users to crash the process with crafted JavaScript. During nested Function.apply calls, mbuf_insert reallocates the backing buffer while mjs_apply retains and later reads a pointer into the freed allocation. Exploitation requires execution of attacker-supplied JavaScript in a local or embedding context; the published reproducer demonstrates a sanitizer-detected abort, not code execution.
Summary
What happened
Heap use-after-free in mjs_apply in Cesanta mJS 2.20.0 allows local users to crash the process with crafted JavaScript. During nested Function.apply calls, mbuf_insert reallocates the backing buffer while mjs_apply retains and later reads a pointer into the freed allocation. Exploitation requires execution of attacker-supplied JavaScript in a local or embedding context; the published reproducer demonstrates a sanitizer-detected abort, not code execution.
The record
- CVE
- CVE-2021-46525
- Published
- Jan 27, 2022
- Updated
- Aug 4, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-416, T1499.004
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 27, 2022CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
- mjs_apply heap-use-after-free reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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