Security readout for executives and security teams
Plain-English summary
CVE-2018-10191 is a memory-safety flaw in mruby up to 1.4.0. If an attacker can make the system run crafted Ruby code, deep scope nesting may trigger memory corruption and possibly arbitrary code execution.
Executive priority
Prioritize remediation for internet-facing or multi-tenant systems that expose mruby scripting. For internal-only embedded use without untrusted Ruby input, treat as important lifecycle remediation.
Technical view
The issue is an integer overflow in src/vm.c mrb_vm_exec() while handling OP_GETUPVAR with deep scope nesting. The overflow can produce a use-after-free condition. Upstream references include issue 3995 and commit 1905091634a6a2925c911484434448e568330626.
Likely exposure
Exposure is most likely in products, appliances, services, or scripts embedding mruby up to and including 1.4.0, especially where users can supply or influence Ruby code.
Exploitation context
The source bundle does not show KEV listing or confirmed active exploitation. Exploitation requires an attacker-controlled path to run Ruby code inside mruby, which limits reach but raises impact where scripting is exposed.
Researcher notes
Evidence is specific on root cause and impact but sparse on scoring. No CVSS, CWE, or complete affected CPE data is provided. Avoid assuming exposure beyond mruby versions up to 1.4.0 and downstream packages or embedded copies.
Mitigation direction
- Upgrade mruby to a release containing the upstream fix commit.
- Apply Debian DLA 2996-1 packages where Debian LTS mruby is used.
- Restrict untrusted users from submitting Ruby code to mruby runtimes.
- Isolate or sandbox mruby execution where scripting must remain enabled.
- Check embedded product vendor guidance for bundled mruby updates.
Validation and detection
- Inventory systems and dependencies for mruby versions up to 1.4.0.
- Check embedded firmware or application bundles, not only OS packages.
- Confirm the upstream fix commit or vendor backport is present.
- Identify workflows that execute user-controlled Ruby code.
- Review Debian package status against DLA 2996-1 where applicable.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
Execution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2018-10191 mapping review
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Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/mruby/mruby/issues/3995CVE reference · x_refsource_MISC
- https://github.com/mruby/mruby/commit/1905091634a6a2925c911484434448e568330626CVE reference · x_refsource_MISC
- [debian-lts-announce] 20220506 [SECURITY] [DLA 2996-1] mruby security updateCVE reference · mailing-list, x_refsource_MLIST
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.