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TI-2026-74679 Aliases CVE-2026-109855GHSA-qq8j-7v2v-3rwp

Denial of service in undici WebSocket client over HTTP/2

Priority LOW 39CWE-248Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 2 fixed, 8 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-248.

Summary

undici versions from 8.11.0 before 8.11.2 are affected, the undici package for Node.js. Its experimental WebSocket client mishandles a failed WebSocket handshake over HTTP/2, leaving the HTTP/2 stream open without an error listener (CWE-248). A malicious server that destroys the connection triggers an unhandled error that exits the Node.js process. A remote, unauthenticated server can crash any client that opens a WebSocket to it over HTTP/2.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

undici is an HTTP client library for Node.js. In versions 8.11.0 and 8.11.1, its experimental WebSocket client, which is enabled by default when HTTP/2 is allowed, mishandles a failed WebSocket handshake over HTTP/2: the request is already marked completed, so the abort becomes a no-op and the underlying HTTP/2 stream is left open with no error listener. When a malicious server then destroys the connection, the orphaned stream emits an unhandled error and the Node.js process exits. A remote, unauthenticated server can therefore crash any client that opens a WebSocket to it over HTTP/2, resulting in a denial of service. The issue is fixed in undici 8.11.2, and users should upgrade to 8.11.2 or later. As a workaround, set allowH2 to false to disable HTTP/2 for WebSocket connections, or avoid opening WebSocket connections to untrusted servers.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00279 20th percentileScored 2026-11-07
Fix Partial undici (undici): 8.11.2undici (npm): 8.11.2Red Hat: 4 advisoriesRed Hat: 2 fixed, 8 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
NodeJSundici8.11.0 to before 8.11.28.11.2Patch availableCNA
—undici (npm)8.11.0 to before 8.11.28.11.2Patch availableGHSA-qq8j-7v2v-3rwp
  • undici VendorNodeJS Affected 8.11.0 to before 8.11.2 Fixed in 8.11.2 Patch available CNA
  • undici (npm) Vendor— Affected 8.11.0 to before 8.11.2 Fixed in 8.11.2 Patch available GHSA-qq8j-7v2v-3rwp

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*8.11.0 to before 8.11.2VulnerableNodeJS
  • cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:* Versions 8.11.0 to before 8.11.2 Vulnerable ·NodeJS

Remediation

Upgrade undici to version 8.11.2 or later. Red Hat fixes are listed in RHSA-2026:95591, RHSA-2026:95081, RHSA-2026:83198 and RHSA-2026:76677 for Cluster Observability Operator 1.5 and Red Hat Hardened Images. The sources list no fixed version for Red Hat AMQ Broker 7, Red Hat OpenShift AI (RHOAI), Red Hat OpenShift Container Platform 5, Red Hat OpenShift Dev Spaces, Red Hat Openshift Data Foundation 4 and Secrets Management Console for Red Hat OpenShift. As a workaround, set allowH2 to false to disable HTTP/2 for WebSocket connections.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA undici (undici) Fixed in 8.11.2
  • Fix · GHSA-qq8j-7v2v-3rwp undici (npm) Fixed in 8.11.2 Advisory →

Red Hat 4 advisories

  • RHSA-2026:95591 Released 2026-11-05 · Red Hat rating Important
    Cluster Observability Operator - 1.5
    • Cluster Observability Operator 1.5 registry.redhat.io/cluster-observability-operator/alertmanager-rhel9, registry.redhat.io/cluster-observability-operator/cluster-observability-rhel9-operator, registry.redhat.io/cluster-observability-operator/distributed-tracing-console-plugin-pf4-rhel9 +16
  • RHSA-2026:95081 Released 2026-11-04 · Red Hat rating Important
    Cluster Observability Operator - 1.5
    • Cluster Observability Operator 1.5 registry.redhat.io/cluster-observability-operator/alertmanager-rhel9, registry.redhat.io/cluster-observability-operator/cluster-observability-rhel9-operator, registry.redhat.io/cluster-observability-operator/distributed-tracing-console-plugin-pf4-rhel9 +16
  • RHSA-2026:83198 Released 2026-10-14 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images nodejs26-26.11.1-0.3.hum1@aarch64, nodejs26-26.11.1-0.3.hum1@s390x, nodejs26-26.11.1-0.3.hum1@src +22
Show 1 more Red Hat advisories
  • RHSA-2026:76677 Released 2026-10-06 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images grafana12.4-12.4.12-0.4.hum1@aarch64, grafana12.4-12.4.12-0.4.hum1@src, grafana12.4-12.4.12-0.4.hum1@x86_64

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Exploit IntelligenceAffectedNo fix yet
Red Hat AMQ Broker 7AffectedNo fix yet
Red Hat Hardened ImagesAffectedNo fix planned: Will not fix
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet
Red Hat OpenShift Container Platform 5AffectedNo fix yet
Red Hat OpenShift Dev SpacesAffectedNo fix yet
Red Hat Openshift Data Foundation 4AffectedNo fix yet
Secrets Management Console for Red Hat OpenShiftAffectedNo fix planned: Will not fix
Cluster Observability Operator 1.5Fixed RHSA-2026:95081, RHSA-2026:95591
Red Hat Hardened ImagesFixed RHSA-2026:76677, RHSA-2026:83198
Not affected: 16 products
  • Cluster Observability Operator 1.5
  • Cryostat 4
  • Red Hat AMQ Broker 7
  • Red Hat Ansible Automation Platform 2
  • Red Hat Build of Podman Desktop
  • Red Hat Developer Hub 1
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat Hardened Images
  • Red Hat OpenShift AI (RHOAI)
  • Red Hat OpenShift Container Platform 4
  • Red Hat OpenShift Dev Spaces
  • Red Hat Openshift Data Foundation 4
  • Red Hat Trusted Artifact Signer
  • Self-service automation portal 2

Timeline

  1. 2026-10-16 Threatist record created from CVE-2026-109855
  2. 2026-10-16 Fix available: RHSA-2026:83198 · Red Hat
  3. 2026-10-16 Fix available: RHSA-2026:76677 · Red Hat
  4. 2026-10-16 Fix available: Red Hat Hardened Images · Red Hat
  5. 2026-10-16 CVSS score added · Red Hat
  6. 2026-10-18 Affected versions changed · Red Hat
  7. 2026-10-20 Affected versions changed · Red Hat
  8. 2026-10-20 CVSS score changed · Red Hat
  9. 2026-10-27 Affected versions changed · Red Hat
  10. 2026-10-27 Alias added: GHSA-qq8j-7v2v-3rwp
  11. 2026-10-30 Affected versions changed · Red Hat
  12. 2026-11-04 Fix available: RHSA-2026:95081 · Red Hat
  13. 2026-11-04 Fix available: Cluster Observability Operator 1.5 · Red Hat
  14. 2026-11-06 Affected versions changed · Red Hat
  15. 2026-11-06 Fix available: RHSA-2026:95591 · Red Hat

References

Advisory 3

Other 4

  • TI-2026-01215 undici is vulnerable to Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') CVSS 3.1CRITICAL 9.8
  • TI-2022-16376 `undici.request` vulnerable to SSRF using absolute URL on `pathname` CVSS 3.1CRITICAL 9.8
  • TI-2023-09734 CRLF Injection in Nodejs ‘undici’ via host CVSS 3.1MEDIUM 6.5
  • TI-2022-13193 CRLF injection in request headers CVSS 3.1MEDIUM 6.5
  • TI-2022-16375 CRLF Injection in Nodejs ‘undici’ via Content-Type CVSS 3.1MEDIUM 5.3
  • TI-2022-13194 Uncleared cookies on cross-host/cross-origin redirect in undici CVSS 3.1MEDIUM 6.5
See all 51 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences