CVE-2026-6733
undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse
Description
Impact: Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests. This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse. Patches: Upgrade to undici v6.26.0, v7.28.0 or v8.5.0. Workarounds: Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.
INFO
Published Date :
June 17, 2026, 6:18 p.m.
Last Modified :
June 27, 2026, 11:46 p.m.
Remotely Exploit :
No
Source :
ce714d77-add3-4f53-aff5-83d477b104bb
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | LOW | ce714d77-add3-4f53-aff5-83d477b104bb | ||||
| CVSS 3.1 | LOW | MITRE-CVE |
Solution
- Upgrade to Undici v6.26.0, v7.28.0, or v8.5.0.
- Set keepAliveTimeout to 0 on Client or Pool.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-6733.
| URL | Resource |
|---|---|
| https://cna.openjsf.org/security-advisories.html | Vendor Advisory |
| https://github.com/nodejs/undici/security/advisories/GHSA-35p6-xmwp-9g52 | Mitigation Vendor Advisory |
| https://hackerone.com/reports/3582376 | Issue Tracking |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-6733 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-6733
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-6733 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-6733 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 27, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:* versions from (including) 8.0.0 up to (excluding) 8.5.0 *cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:* versions up to (excluding) 6.27.0 *cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:* versions from (including) 7.0.0 up to (excluding) 7.28.0 Added Reference Type openjs: https://cna.openjsf.org/security-advisories.html Types: Vendor Advisory Added Reference Type openjs: https://github.com/nodejs/undici/security/advisories/GHSA-35p6-xmwp-9g52 Types: Mitigation, Vendor Advisory Added Reference Type openjs: https://hackerone.com/reports/3582376 Types: Issue Tracking -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-6733', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-17T18:30:07.748616Z'} -
New CVE Received by ce714d77-add3-4f53-aff5-83d477b104bb
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'undici', 'product': 'undici', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '6.26.0', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.26.0', 'versionType': 'semver'}, {'status': 'affected', 'version': '7.0.0', 'lessThan': '7.28.0', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '7.28.0', 'versionType': 'semver'}, {'status': 'affected', 'version': '8.0.0', 'lessThan': '8.5.0', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '8.5.0', 'versionType': 'semver'}], 'packageURL': 'pkg:npm/undici', 'defaultStatus': 'unaffected'}] Added Description Impact: Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests. This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse. Patches: Upgrade to undici v6.26.0, v7.28.0 or v8.5.0. Workarounds: Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N Added CWE CWE-367 Added Reference https://cna.openjsf.org/security-advisories.html Added Reference https://github.com/nodejs/undici/security/advisories/GHSA-35p6-xmwp-9g52 Added Reference https://hackerone.com/reports/3582376