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CVE Record

CVE-2018-12248: An issue was discovered in mruby 1.4.1.

An issue was discovered in mruby 1.4.1. There is a heap-based buffer over-read associated with OP_ENTER because mrbgems/mruby-fiber/src/fiber.c does not extend the stack in cases of many arguments to fiber.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2018-12248 is a memory-read bug in mruby 1.4.1 fiber handling. In affected builds, a fiber invoked with many arguments may read beyond a heap buffer. Business urgency depends on whether mruby processes untrusted scripts or inputs. The provided sources do not show active exploitation.

Executive priority

Treat this as an inventory-driven remediation item, not a confirmed emergency. Prioritize exposed products that run untrusted mruby code or accept user-controlled scripts. Lack of CVSS and exploitation evidence lowers certainty, but memory safety bugs in embedded runtimes can become operationally significant.

Technical view

The issue is a heap-based buffer over-read associated with OP_ENTER in mrbgems/mruby-fiber/src/fiber.c. The stack was not extended for cases with many arguments to a fiber. CVSS, CWE, and precise affected product metadata are not provided in the source bundle.

Likely exposure

Exposure is most likely where applications embed mruby 1.4.1 with mruby-fiber enabled and allow untrusted or user-influenced Ruby execution. The bundle does not identify downstream products, packages, operating systems, or fixed release numbers.

Exploitation context

CISA KEV status is false in the bundle, and no cited source states active exploitation. The public GitHub issue and commit indicate disclosure and a code fix, but the bundle does not provide exploit maturity, attack prevalence, or real-world incident evidence.

Researcher notes

The strongest evidence is the CVE description plus the upstream GitHub issue and fixing commit. Key gaps are exploitability details, fixed version mapping, CVSS, CWE, and downstream affected products. Avoid assuming impact beyond heap over-read without target-specific analysis.

Mitigation direction

  • Inventory applications and appliances that embed mruby 1.4.1.
  • Check whether mruby-fiber is built or used in those deployments.
  • Upgrade to a mruby release or revision containing commit 778500563a9f7ceba996937dc886bd8cde29b42b.
  • If upgrade timing is unclear, follow current mruby vendor or maintainer guidance.
  • Restrict untrusted mruby script execution until affected instances are remediated.

Validation and detection

  • Confirm mruby version and build configuration in each affected application.
  • Review dependency manifests, vendored source, and firmware bills of materials for mruby 1.4.1.
  • Verify whether the referenced fixing commit is present in deployed source or packages.
  • Check logs and crash reports for unusual mruby fiber-related failures.
  • Document systems where exposure cannot be confirmed and assign owners for follow-up.
Prepared
Confidence
medium
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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

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CVE-2018-12248 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.