CVE-2020-6840
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
- Record
CVE-2020-6840- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-416
- Updated
- 2026-11-02
CVE List No score
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
- Record
CVE-2020-6840- Updated
- 2026-11-02
EUVDEUVD-2020-27983 No score
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
- Record
EUVD-2020-27983- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4v2f-5xhv-8ff4 No score
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
- Record
GHSA-4v2f-5xhv-8ff4- Updated
- 2026-11-02
OSV
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
- Record
CVE-2020-6840- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2020-6840
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c.
- Record
UBUNTU-CVE-2020-6840- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
mrubyUbuntu:16.04:LTS |
All versions, plus listed versions 1.1.0+20150817+gita1731254-11.1.0+20150906+git1cbbb7e1-11.2.0+20160315+git4f20d58a-1 |
None known |
mrubyUbuntu:18.04:LTS |
All versions, plus listed versions 1.3.0-11.3.0+20170925+git38185028-11.3.0+20171029+git77edafb0-11.4.0-1 |
None known |
mrubyUbuntu:20.04:LTS |
All versions, plus listed versions 2.0.0-1 |
None known |
mrubyUbuntu:22.04:LTS |
All versions, plus listed versions 2.1.2-33.0.0-13.0.0-3 |
None known |
mrubyUbuntu:24.04:LTS |
All versions, plus listed versions 3.2.0-13.2.0-2 |
None known |
mrubyUbuntu:25.10 |
All versions, plus listed versions 3.3.0-1 |
None known |
mrubyUbuntu:26.10 |
All versions, plus listed versions 3.4.0-23.4.0-34.0.0-1 |
None known |
mrubyUbuntu:26.04:LTS |
All versions, plus listed versions 3.3.0-13.4.0-2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-6840 is a critical vulnerability (CVSS 9.8) in Mruby, published January 11, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.50%, the 74th percentile. No source names a fixed version.