CVE-2020-6840
CWE-416Published: January 11, 2020· Updated: Jun 17, 2026
Official Description
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
Technical Analysis
CVE-2020-6840 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.
From a weakness classification perspective (CWE-416): Use-after-free vulnerabilities involve accessing memory after it has been freed, often enabling arbitrary code execution.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (2)
Quick Facts
Related CVEs (CWE-416)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2020-6840 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts