Mruby
CVE-2020-6839
CRITICAL
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available. |
| Exploit ScenarioDerived | A remote attacker could write data beyond allocated buffer boundaries leading to code execution or crashes by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
In mruby 2.1.0, there is a stack-based buffer overflow in mrb_str_len_to_dbl in string.c. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. In mruby 2.1.0, there is a stack-based buffer overflow in mrb_str_len_to_dbl in string.c. Affected products include: Mruby.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
In mruby 2.1.0, there is a stack-based buffer overflow in mrb_str_len_to_dbl in string.c.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
Affected Products (CPE)NVD
heap-buffer-overflow in mrb_vm_exec in mruby/mruby in GitHub repository mruby/mruby prior to 3.2. Rated critical severit
Out-of-bounds Read in mrb_get_args in GitHub repository mruby/mruby prior to 3.2. Rated critical severity (CVSS 9.8), th
Use-After-Free in str_escape in mruby/mruby in GitHub repository mruby/mruby prior to 3.2. Rated critical severity (CVSS
Heap-based Buffer Overflow in Homebrew mruby prior to 3.2. Rated critical severity (CVSS 9.8), this vulnerability is rem
mruby is vulnerable to Heap-based Buffer Overflow. Rated critical severity (CVSS 9.8), this vulnerability is remotely ex
mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrec
In mruby 2.1.0, there is a use-after-free in hash_slice in mrbgems/mruby-hash-ext/src/hash-ext.c. Rated critical severit
In mruby 2.1.0, there is a use-after-free in hash_values_at in mrbgems/mruby-hash-ext/src/hash-ext.c. Rated critical sev
The init_copy function in kernel.c in mruby 1.4.1 makes initialize_copy calls for TT_ICLASS objects, which allows attack
In versions of mruby up to and including 1.4.0, an integer overflow exists in src/vm.c::mrb_vm_exec() when handling OP_G
use after free in mrb_vm_exec in GitHub repository mruby/mruby prior to 3.2. Rated critical severity (CVSS 9.1), this vu
Out-of-bounds Read in GitHub repository mruby/mruby prior to 3.2. Rated critical severity (CVSS 9.1), this vulnerability
Exploit-DB