CVE-2020-6839
CVE-2020-6839 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: 1% (68th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-787
- Affected product: Mruby
- Published:
- Last modified:
Description
In mruby 2.1.0, there is a stack-based buffer overflow in mrb_str_len_to_dbl in string.c.
Frequently asked questions
- What is CVE-2020-6839?
- In mruby 2.1.0, there is a stack-based buffer overflow in mrb_str_len_to_dbl in string.c.
- How severe is CVE-2020-6839?
- CVE-2020-6839 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-2020-6839 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2020-6839?
- CVE-2020-6839 affects Mruby. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2020-6839?
- 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-2020-6839 published?
- CVE-2020-6839 was published on 2020-01-11 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:mruby:mruby:2.1.0:*:*:*:*:*:*:*
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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