CVE-2018-12248

An issue was discovered in mruby 1.4.1. There is a heap-based buffer over-read associated with...

7.5 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

1.49%Up 0.9 points since Apr 14, 2021

What each source reports

NVD Score used 7.5

Record: CVE-2018-12248
CVSS 3.0: 7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:N/I:N/A:P
Weakness: CWE-125
Updated: 2026-11-02

CVE List No score

Record: CVE-2018-12248
Updated: 2026-11-02

EUVDEUVD-2018-4226 No score

Record: EUVD-2018-4226
Updated: 2026-11-03

GitHub AdvisoriesGHSA-96p2-24jg-gc5w 7.5

An issue was discovered in mruby 1.4.1. There is a heap-based buffer over-read associated with...

Record: GHSA-96p2-24jg-gc5w
CVSS 3.0: 7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-125
Updated: 2026-11-02

OSV 7.5

Record: CVE-2018-12248
CVSS 3.0: 7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVDEBIAN-CVE-2018-12248 7.5

Record: DEBIAN-CVE-2018-12248
CVSS 3.0: 7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2018-12248 7.5

Record: UBUNTU-CVE-2018-12248
CVSS 3.0: 7.5 HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

Affected products

mruby

Affected packages

Affected packages
Package	Affected	Fixed
`mruby` Debian:12	before 1.4.1+20180622+git640fca32-1	1.4.1+20180622+git640fca32-1
`mruby` Debian:13	before 1.4.1+20180622+git640fca32-1	1.4.1+20180622+git640fca32-1
`mruby` Debian:14	before 1.4.1+20180622+git640fca32-1	1.4.1+20180622+git640fca32-1
`mruby` Ubuntu:16.04:LTS	All versions, plus listed versions 1.1.0+20150817+gita1731254-11.1.0+20150906+git1cbbb7e1-11.2.0+20160315+git4f20d58a-1	None known
`mruby` Ubuntu:18.04:LTS	All versions, plus listed versions 1.3.0-11.3.0+20170925+git38185028-11.3.0+20171029+git77edafb0-11.4.0-1	None known
`mruby` Ubuntu:20.04:LTS	All versions, plus listed versions 2.0.0-1	None known
`mruby` Ubuntu:22.04:LTS	All versions, plus listed versions 2.1.2-33.0.0-13.0.0-3	None known
`mruby` Ubuntu:24.04:LTS	All versions, plus listed versions 3.2.0-13.2.0-2	None known
`mruby` Ubuntu:25.10	All versions, plus listed versions 3.3.0-1	None known
`mruby` Ubuntu:26.10	All versions, plus listed versions 3.4.0-23.4.0-34.0.0-1	None known
`mruby` Ubuntu:26.04:LTS	All versions, plus listed versions 3.3.0-13.4.0-2	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-12248 is a high vulnerability (CVSS 7.5) in Mruby, published June 12, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.49%, the 74th percentile. Fixed in mruby 1.4.1+20180622+git640fca32-1.