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CVE-2026-6733

undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse

Published: Jun 17, 2026Updated: Jun 17, 2026 Sources: CVE List NVDCWE-367
NVD MITRE
3.7CVSSLOW
EPSS Score
0.2%
Top 92.7%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

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.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:NI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-367

Affected Products

undiciundici
On-prem
OSS Libraries / npm
undicioss-projectOSS Librariesaka undici

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

1 technique
Privilege Escalation
View detailed technique mapping

References

https://github.com/nodejs/undici/security/advisories/GHSA-35p6-xmwp-9g52
github.com
https://hackerone.com/reports/3582376
hackerone.com
https://cna.openjsf.org/security-advisories.html
cna.openjsf.org

Timeline

Published
Jun 17, 2026
Last Updated
Jun 17, 2026

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