Buffer overflow in Mruby
CVE-2025-12875
A weakness has been identified in mruby 3.4.0. This vulnerability affects the function ary_fill_exec of the file mrbgems/mruby-array-ext/src/array.c. Executing a manipulation of the argument start/length can lead to out-of-bounds write. The attack needs to be launched locally. The exploit has been made available to the public and could be used for attacks. This patch is called 93619f06dd378db6766666b30c08978311c7ec94. It is best practice to apply a patch to resolve this issue.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.002 (4.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 4.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- Mruby — versions 3.4.0
- Mruby — versions 3.4.0
Weakness classification (CWE)
References
- vuldb.com/ (technical-description, VDB Entry, Third Party Advisory, vdb-entry)
- vuldb.com/ (signature, Permissions Required, permissions-required, VDB Entry)
- vuldb.com/ (VDB Entry, Third Party Advisory, third-party-advisory)
- github.com/mruby/mruby/issues/6650 (issue-tracking, Issue Tracking)
- github.com/mruby/mruby/issues/6650 (issue-tracking, Issue Tracking)
- github.com/mruby/mruby/issues/6650 (issue-tracking, Patch, exploit)
- github.com/makesoftwaresafe/mruby/commit/93619f06dd378db6766666b30c08978311c7ec… (Patch, patch)
- github.com/mruby/mruby/ (product)
Frequently asked questions
- What is CVE-2025-12875?
- CVE-2025-12875 is a medium-severity vulnerability in Mruby, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 5.3/10. Published 2025-11-07.
- How severe is CVE-2025-12875?
- Medium severity. CVSS v3 base score is 5.3 out of 10.