CVE-2020-15866
CVE-2020-15866 is a critical-severity vulnerability in Mruby with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v2: 7.5
- EPSS exploit prediction: 2% (79th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-787
- Affected product: Mruby
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2020-15866?
- CVE-2020-15866 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2020-15866 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-15866?
- CVE-2020-15866 primarily affects Mruby. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2020-15866?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- When was CVE-2020-15866 published?
- CVE-2020-15866 was published on 2020-07-21 and last updated on 2026-06-17.
References
- https://github.com/mruby/mruby/issues/5042
- https://lists.debian.org/debian-lts-announce/2022/05/msg00006.html
Affected products (3)
- cpe:2.3:a:mruby:mruby:*:*:*:*:*:*:*:*
- cpe:2.3:a:mruby:mruby:2.1.2:rc:*:*:*:*:*:*
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
More vulnerabilities in Mruby
- CVE-2022-1286 — Critical (CVSS 9.8): heap-buffer-overflow in mrb_vm_exec in mruby/mruby in GitHub repository mruby/mruby prior to 3.2. Possible arbitrary…
- CVE-2022-1276 — Critical (CVSS 9.8): Out-of-bounds Read in mrb_get_args in GitHub repository mruby/mruby prior to 3.2. Possible arbitrary code execution if…
- CVE-2022-1212 — Critical (CVSS 9.8): Use-After-Free in str_escape in mruby/mruby in GitHub repository mruby/mruby prior to 3.2. Possible arbitrary code…
- CVE-2022-0631 — Critical (CVSS 9.8): Heap-based Buffer Overflow in Homebrew mruby prior to 3.2.
- CVE-2022-0570 — Critical (CVSS 9.8): Heap-based Buffer Overflow in Homebrew mruby prior to 3.2.
- CVE-2022-0080 — Critical (CVSS 9.8): mruby is vulnerable to Heap-based Buffer Overflow
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