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Full vulnerability report · 2026
CVE-2026-6733High confidence

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

undici · undici

3.7LowCVSS 3.1
Recommended action
Scheduled

Low technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

1 package state
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · standard archivenode-undiciUnder evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical record ↗Source updated 8 Sept 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-6733 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityundici: Undici: Response queue poisoning on reused keep-alive sockets can lead to incorrect response delivery.
43 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • cryostat-openshift-console-plugin-npm as a component of Cryostat 4
  • grafana-infinity-datasource-npm as a component of Cryostat 4
  • undici as a component of Cryostat 4
  • openshift-pipelines/pipelines-console-plugin-pf5-rhel9 as a component of OpenShift Pipelines
  • openshift-pipelines/pipelines-console-plugin-rhel8 as a component of OpenShift Pipelines
  • openshift-pipelines/pipelines-console-plugin-rhel9 as a component of OpenShift Pipelines
  • undici as a component of Red Hat AMQ Broker 7
  • rh-podman-desktop.git as a component of Red Hat Build of Podman Desktop
  • rhdh/rhdh-hub-rhel9 as a component of Red Hat Developer Hub
  • nodejs as a component of Red Hat Enterprise Linux 8
  • nodejs-devel as a component of Red Hat Enterprise Linux 8
  • nodejs-docs as a component of Red Hat Enterprise Linux 8
Summary
A flaw was found in undici. An attacker-controlled upstream server can exploit a vulnerability in Undici's HTTP/1.1 client, specifically related to response queue poisoning on reused keep-alive sockets. This allows the attacker to inject an unsolicited HTTP/1.1 response onto an idle socket. Consequently, when the client dispatches a new request on that socket, it may associate the injected response with the new request, leading to responses being delivered to unintended recipients or requests. This could result in a low impact on data integrity.
Remediation
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-37769

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Low technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

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.

What

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.

Why

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Time-of-check Time-of-use (TOCTOU) Race Condition → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-367 ↗

CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-367
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2026-2919IBM App Connect Enterprise: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise ausnutzen, um beliebigen Programmcode auszuführen, um seine Privilegien zu erhöhen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, um einen Cross-Site Scripting Angriff durchzuführen, und um Sicherheitsvorkehrungen zu umgehen.

Official advisory
BSI · German · WID-SEC-W-2026-2618IBM App Connect Enterprise: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, und um Daten zu manipulieren.

Official advisory
CERT-FR · French · CERTFR-2026-AVI-1094Multiples vulnérabilités dans les produits IBM

d?id=CVE-2026-64958 Référence CVE CVE-2026-65898 https://www.cve.org/CVERecord?id=CVE-2026-65898 Référence CVE CVE-2026-65899 https://www.cve.org/CVERecord?id=CVE-2026-65899 Référence CVE CVE-2026-65900 https://www.cve.org/CVERecord?id=CVE-2026-65900 Référence CVE CVE-2026-66053 https://www.cve.org/CVERecord?id=CVE-2026-66053 Référence CVE CVE-2026-66142 https://www.cve.org/CVERecord?id=CVE-2026-66142 Référence CVE CVE-2026-66143 https://www.cve.org/CVERecord?id=CVE-2026-66143 Référence CVE CVE-2026-66144 https://www.cve.org/CVERecord?id=CVE-2026-66144 Référence CVE CVE-2026-66373 https://www.cve.org/CVERecord?id=CVE-2026-66373 Référence CVE CVE-2026-6733 https://www.cve.org/CVERecord?id=CVE-2026-6733 Référence CVE CVE-2026-6734 https://www.cve.org/CVERecord?id=CVE-2026-6734 Référence CVE CVE-2026-6790 https://www.cve.org/CVERecord?id=CVE-2026-6790 Référence CVE CVE-2026-6918 https://www.cve.org/CVERecord?id=CVE-2026-6918 Référence CVE CVE-2026-69247 https://www.cve.org/CVERecord?id=CVE-2026-69247 Référence CVE CVE-2026-69248 https://www.cve.org/CVERecord?id=CVE-2026-69248 Référence CVE CVE-2026-69249 https://www.cve.org/CVERecord?id=CVE-2026-69249 Référence CVE CVE-2026-7246 https://www.cve.org/CVERecord?id=CVE-2026-7246 Référence CVE CVE-2026-75838 https://www.cve.org/CVERecord?id=CVE-2026-

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
cryostat-openshift-console-plugin-npm as a component of Cryostat 4; grafana-infinity-datasource-npm as a component of Cryostat 4; undici as a component of Cryostat 4; openshift-pipelines/pipelines-console-plugin-pf5-rhel9 as a component of OpenShift Pipelines; openshift-pipelines/pipelines-console-plugin-rhel8 as a component of OpenShift Pipelines; openshift-pipelines/pipelines-console-plugin-rhel9 as a component of OpenShift Pipelines; undici as a component of Red Hat AMQ Broker 7; rh-podman-desktop.git as a component of Red Hat Build of Podman Desktop; rhdh/rhdh-hub-rhel9 as a component of Red Hat Developer Hub; nodejs as a component of Red Hat Enterprise Linux 8; nodejs-devel as a component of Red Hat Enterprise Linux 8; nodejs-docs as a component of Red Hat Enterprise Linux 8; nodejs-full-i18n as a component of Red Hat Enterprise Linux 8; nodejs-libs as a component of Red Hat Enterprise Linux 8; nodejs-nodemon as a component of Red Hat Enterprise Linux 8; nodejs-nodemon.src as a component of Red Hat Enterprise Linux 8; nodejs-packaging as a component of Red Hat Enterprise Linux 8; nodejs-packaging-bundler as a component of Red Hat Enterprise Linux 8; nodejs-packaging.src as a component of Red Hat Enterprise Linux 8; nodejs.src as a component of Red Hat Enterprise Linux 8; npm as a component of Red Hat Enterprise Linux 8; v8-12.4-devel as a component of Red Hat Enterprise Linux 8; v8-13.6-devel as a component of Red Hat Enterprise Linux 8; nodejs25.src as a component of Red Hat Hardened Images; rust.src as a component of Red Hat Hardened Images; rhoai/odh-dashboard-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-automl-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-autorag-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-eval-hub-rhel9 as a component of Red Hat OpenShift AI (RHOAI); rhoai/odh-mod-arch-gen-ai-rhel9 as a component of Red Hat OpenShift AI (RHOAI); and 13 more
Fixed
nodejs-1:22.23.1-2.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-1:22.23.1-2.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-1:22.23.1-2.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-1:22.23.1-2.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-debuginfo-1:22.23.1-2.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-debuginfo-1:22.23.1-2.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-debuginfo-1:22.23.1-2.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-debuginfo-1:22.23.1-2.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-devel-1:22.23.1-2.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-devel-1:22.23.1-2.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-devel-1:22.23.1-2.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-devel-1:22.23.1-2.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-docs-1:22.23.1-2.el10_2.noarch as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-full-i18n-1:22.23.1-2.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-full-i18n-1:22.23.1-2.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-full-i18n-1:22.23.1-2.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-full-i18n-1:22.23.1-2.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-libs-1:22.23.1-2.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-libs-1:22.23.1-2.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-libs-1:22.23.1-2.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-libs-1:22.23.1-2.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-libs-debuginfo-1:22.23.1-2.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-libs-debuginfo-1:22.23.1-2.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-libs-debuginfo-1:22.23.1-2.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-libs-debuginfo-1:22.23.1-2.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-npm-1:10.9.8-1.22.23.1.2.el10_2.aarch64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-npm-1:10.9.8-1.22.23.1.2.el10_2.ppc64le as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-npm-1:10.9.8-1.22.23.1.2.el10_2.s390x as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs-npm-1:10.9.8-1.22.23.1.2.el10_2.x86_64 as a component of Red Hat Enterprise Linux AppStream (v. 10); nodejs22-1:22.23.1-2.el10_2.src as a component of Red Hat Enterprise Linux AppStream (v. 10); and 281 more
Action
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Workaround
A mitigation or workaround reference is available from the source linked below; validate it against the affected product and version.
04

Evidence and provenance

Published 17 Jun 2026 · Last source change 17 Jun 2026, 18:30 UTC · CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-37769
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-37769↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗Vendor advisory↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-6733 · cve.blacktree.nl