CVE-2020-15866
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in...
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.
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
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.
- Record
CVE-2020-15866- 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-787
- Updated
- 2026-11-02
CVE List No score
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.
- Record
CVE-2020-15866- Updated
- 2026-11-02
EUVDEUVD-2020-7847 No score
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.
- Record
EUVD-2020-7847- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4f9x-p86g-x88m
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in...
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.
- Record
GHSA-4f9x-p86g-x88m- 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 - Weakness
- CWE-787
- Updated
- 2026-11-02
OSVALPINE-CVE-2020-15866
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.
- Record
ALPINE-CVE-2020-15866- 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
- 2026-11-03
OSV
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.
- Record
CVE-2020-15866- 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
OSVDEBIAN-CVE-2020-15866
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.
- Record
DEBIAN-CVE-2020-15866- 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-2020-15866
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.
- Record
UBUNTU-CVE-2020-15866- 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 |
|---|---|---|
mrubyAlpine:v3.13 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyAlpine:v3.14 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyAlpine:v3.15 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyAlpine:v3.16 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyAlpine:v3.17 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyAlpine:v3.18 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyAlpine:v3.19 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyAlpine:v3.20 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyAlpine:v3.21 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyAlpine:v3.22 |
before 2.1.2-r0 | 2.1.2-r0 |
Show 14 moreShow less
| Package | Affected | Fixed |
|---|---|---|
mrubyAlpine:v3.23 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyAlpine:v3.24 |
before 2.1.2-r0 | 2.1.2-r0 |
mrubyDebian:12 |
before 2.1.2-1 | 2.1.2-1 |
mrubyDebian:13 |
before 2.1.2-1 | 2.1.2-1 |
mrubyDebian:14 |
before 2.1.2-1 | 2.1.2-1 |
mrubyDebian:9 From an advisory covering 6 CVEs |
before 1.2.0+20161228+git30d5424a-1+deb9u1, plus listed versions 1.2.0+20161228+git30d5424a-1 |
1.2.0+20161228+git30d5424a-1+deb9u1 |
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 |
|---|---|---|
| affected, facts | ||
| affected, aliases, references | OSV | |
| 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-2020-15866 is a critical vulnerability (CVSS 9.8) in Mruby, published July 21, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.13%, the 82nd percentile. Fixed in mruby 2.1.2-r0.
References
github.com/mruby/mruby/issues/5042
lists.debian.org/debian-lts-announce/2022/05/msg00006.html
nvd.nist.gov/vuln/detail/CVE-2020-15866
security.alpinelinux.org/vuln/CVE-2020-15866
security-tracker.debian.org/tracker/CVE-2020-15866
ubuntu.com/security/CVE-2020-15866
cve.org/CVERecord?id=CVE-2020-15866