# CVE-2026-12151: undici WebSocket client vulnerable to denial of service via fragment count bypass

> CVE-2026-12151: undici WebSocket client vulnerable to denial of service via fragment count bypass. CVSS 7.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-12151
Last updated: 2026-09-11T13:17:05Z

- Published: 2026-06-17 16:05 UTC · Updated: 2026-09-11 13:17 UTC · Assigner: openjs
- CVSS: 7.5 (CVSS 3.1) · Severity: High · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS: 0.79%, 56th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-400, CWE-770

## Description

Impact: The undici WebSocket client enforces maxPayloadSize on the cumulative byte count of fragments in a message but does not enforce a limit on the number of fragments. A malicious WebSocket server can stream many small or empty continuation frames that each pass per-frame and cumulative-size validation, collectively causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service. Affected applications are those using the undici WebSocket client (new WebSocket(...)) or the WebSocketStream API that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint. All releases starting at undici 6.17.0 are affected. Patches: Upgrade to undici \>= 6.26.0, \>= 7.28.0, or \>= 8.5.0. Workarounds: No workaround is available. The fix must be applied through an upgrade.

## Affected vendors and products

- Red Hat: Cluster Observability Operator 1.5.0
- Red Hat: Cryostat 4
- Red Hat: Cryostat 4 on RHEL 9
- Red Hat: OpenShift Pipelines
- Red Hat: Red Hat AMQ Broker 7.13.6
- Red Hat: Red Hat AMQ Broker 7.14.1
- Red Hat: Red Hat Build of Podman Desktop
- Red Hat: Red Hat Enterprise Linux 10
- Red Hat: Red Hat Enterprise Linux 10.0 Extended Update Support
- Red Hat: Red Hat Enterprise Linux 8
- Red Hat: Red Hat Enterprise Linux 9
- Red Hat: Red Hat Enterprise Linux 9.6 Extended Update Support
- Red Hat: Red Hat Hardened Images
- Red Hat: Red Hat OpenShift AI 2.25
- Red Hat: Red Hat OpenShift AI 3.4
- Red Hat: Red Hat OpenShift AI (RHOAI)
- Red Hat: Red Hat OpenShift Container Platform 4
- Red Hat: Red Hat OpenShift Container Platform 4.16
- Red Hat: Red Hat OpenShift Container Platform 4.17
- Red Hat: Red Hat Openshift Data Foundation 4.18
- Red Hat: Self-service automation portal 2
- undici: undici

## Tracked companies

- [Jira](https://rewindex.com/company/jira.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-12151)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-12151)
- [https://cna.openjsf.org/security-advisories.html](https://cna.openjsf.org/security-advisories.html)
- [https://github.com/nodejs/undici/security/advisories/GHSA-vxpw-j846-p89q](https://github.com/nodejs/undici/security/advisories/GHSA-vxpw-j846-p89q)

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_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


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Canonical: https://rewindex.com/cve/CVE-2026-12151 · Markdown: https://rewindex.com/cve/CVE-2026-12151.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-12151 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T02:14:24.785Z