# Remediation Handoff: CVE-2026-16729

## Summary

NVD: undici's setCookie function does not fully sanitize cookie attributes. NVD: In undici before 6.28.0, from 7.0.0 up to before 7.29.0, and from 8.0.0 up to before 8.9.0, a domain value is not checked for semicolons and entries in the unparsed array are not sanitized, so attacker-influenced input can inject additional cookie attributes. NVD: For example, a domain value containing a semicolon can append attributes such as SameSite, and an unparsed entry can inject attributes such as HttpOnly, without the caller setting them.

## Why it matters

CVSS severity is MEDIUM with score 4.8. EPSS percentile is 0.07351. KEV status is not listed in KEV. Use this as a defensive priority handoff, not as an execution instruction.

## Affected context

* Vendor: nodejs
* Product: undici
* Component: unknown
* Version / CPE / PURL: unknown

## Remediation context

* Recommended route: vendor_patch_or_mitigation
* Vendor/advisory reference: official_reference_present
* Patch status: confirmed
* Fixed version: undici
* References: https://cna.openjsf.org/security-advisories.html, https://github.com/nodejs/undici/security/advisories/GHSA-v3r7-h72x-cjcm

## Human checklist

* Confirm whether the listed product or package is present.
* Confirm affected version.
* Review vendor advisory or official source.
* Confirm patch, fixed version, mitigation, workaround, or monitor-only decision.
* Confirm exposure.
* Document remediation status.

## Safe AI / Codex handoff

* Goal: Prepare a defensive remediation plan for CVE-2026-16729 using only provided public-safe source context and any separate repo context supplied by the user.
* Allowed actions: summarize vendor guidance, prepare a defensive remediation plan, identify affected dependencies only when repo context is separately provided by the user, suggest tests and validation steps, document human verification questions
* Disallowed actions: generate offensive code, provide payloads, scan external targets, change production systems, merge or deploy changes, create GitHub issues or pull requests without explicit separate approval
* Acceptance criteria: Affected product or dependency presence is confirmed by a human., Affected version is confirmed or marked not applicable., Official advisory or source reference is reviewed., Patch, fixed version, mitigation, workaround, or monitor-only decision is documented., Validation steps are proposed without external scanning or production mutation.
* Human approval required: true

## Safety note

This handoff is for defensive triage and remediation planning only. It excludes offensive procedure, payload material, external target scan guidance, and auto-remediation.