CVE-2025-12875: mruby array.c ary_fill_exec out-of-bounds write

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-11-07 · updated 2026-10-19
Weakness: CWE-119

Description

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.

Affected products

mruby/mruby: 3.4.0

References

https://github.com/makesoftwaresafe/mruby/commit/93619f06dd378db6766666b30c08978311c7ec94
https://github.com/mruby/mruby/
https://github.com/mruby/mruby/issues/6650
https://github.com/mruby/mruby/issues/6650#event-20443453808
https://github.com/mruby/mruby/issues/6650#issuecomment-3430851605
https://vuldb.com/?ctiid.331511
https://vuldb.com/?id.331511
https://vuldb.com/?submit.680879
https://github.com/mruby/mruby/issues/6650
https://github.com/mruby/mruby/issues/6650#issuecomment-3430851605

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