CVE-2026-16729: undici vulnerable to cookie attribute injection via unsanitized domain and unparsed setCookie fields
CVE-2026-16729 is a vulnerability in undici vulnerable to cookie attribute injection via unsanitized domain and unparsed setCookie fields, rated Moderate by Microsoft, with a CVSS 3.1 base score of 4.8 (Medium). An attacker can exploit it remotely over the network, without any privileges and without user interaction. Microsoft has not reported exploitation in the wild. The EPSS model estimates a 0.28% probability of exploitation activity in the next 30 days, higher than 21% of all scored vulnerabilities. Microsoft released the fix on 6 August 2026, outside Patch Tuesday. It affects 3 products in 1 product family (Open Source Software).
Key facts
- CVE ID
- CVE-2026-16729
- Severity
- Medium CVSS 4.8
- Microsoft severity
- Moderate
- Exploited in the wild
- No
- Publicly disclosed
- No
- Weakness
- CWE-74
- EPSS
- 0.28% (percentile 21%)
- CISA KEV
- Not listed
- Released
- Last updated
- Patch Tuesday
- July 2026 Patch Tuesday
- Product families
- Open Source Software
CVSS score and vector
Microsoft scores CVE-2026-16729 at 4.8 (temporal 4.8) using CVSS 3.1. Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
| Metric | Value |
|---|---|
| Attack vector | Network |
| Attack complexity | High |
| Privileges required | None |
| User interaction | None |
| Scope | Unchanged |
| Confidentiality impact | Low |
| Integrity impact | Low |
| Availability impact | None |
Affected products (3)
Open Source Software
| Product | Security update | Type | Fixed build | Restart |
|---|---|---|---|---|
| azl3 nodejs 24.18.1-1 on Azure Linux 3.0 | Security update | Security Update | ||
| azl3 nodejs 24.20.0-1 on Azure Linux 3.0 | Security update | Security Update | ||
| azl3 nodejs 24.21.0-1 on Azure Linux 3.0 | Release Notes | Security Update | 24.22.0-1 |
NIST NVD data
- NVD status
- Analyzed
- NVD CVSS
- 4.8 (MEDIUM)
- NVD weakness
- CWE-74
- Published to NVD
- NVD last modified
Affected configurations (CPE)
| Product | Vulnerable versions |
|---|---|
| undici | before 6.28.0 |
| undici | from 7.0.0, before 7.29.0 |
| undici | from 8.0.0, before 8.9.0 |
References
- https://cna.openjsf.org/security-advisories.html (Vendor Advisory)
- https://github.com/nodejs/undici/security/advisories/GHSA-v3r7-h72x-cjcm (Vendor Advisory)
Revision history
| Version | Date | Description |
|---|---|---|
| 1.0 | Information published. | |
| 2.0 | Information published. | |
| 3.0 | Information published. | |
| 4.0 | Information published. | |
| 5.0 | Information published. | |
| 6.0 | Information published. | |
| 7.0 | Information published. |