Vulnerability 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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nodejs | Undici | >= 6.17.0, < 6.27.0 |
Related Weaknesses (CWE)
References
- https://cna.openjsf.org/security-advisories.htmlVendor Advisory
- https://github.com/nodejs/undici/security/advisories/GHSA-vxpw-j846-p89qVendor Advisory
- https://access.redhat.com/errata/RHSA-2026:34342
- https://access.redhat.com/errata/RHSA-2026:35841
- https://access.redhat.com/errata/RHSA-2026:35842
- https://access.redhat.com/errata/RHSA-2026:35891
- https://access.redhat.com/errata/RHSA-2026:35892
- https://access.redhat.com/errata/RHSA-2026:36621
- https://access.redhat.com/errata/RHSA-2026:36754
- https://access.redhat.com/errata/RHSA-2026:36820
- https://access.redhat.com/errata/RHSA-2026:38009
- https://access.redhat.com/errata/RHSA-2026:38236
- https://access.redhat.com/errata/RHSA-2026:39246
- https://access.redhat.com/errata/RHSA-2026:39868
- https://access.redhat.com/errata/RHSA-2026:41929
FAQ
What is CVE-2026-12151?
CVE-2026-12151 is a vulnerability with a CVSS score of 7.5 (HIGH). 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...
How severe is CVE-2026-12151?
CVE-2026-12151 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-12151?
Check the references section above for vendor advisories and patch information. Affected products include: Nodejs Undici.