CVE-2020-15866 Memory corruption in n/a

What is CVE-2020-15866?

CVE-2020-15866 is a critical memory corruption vulnerability in Debian Debian Linux, published on 21 Jul 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.

Weakness: CWE-787

Which versions are affected by CVE-2020-15866?

It affects 2 products.

Products include Debian Debian Linux, Mruby Mruby.

How do I fix CVE-2020-15866?

Upgrade to a fixed version.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2020-15866 being exploited?

There is no known exploitation of CVE-2020-15866 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2020-15866, GHSA-4f9x-p86g-x88m, UBUNTU-CVE-2020-15866.