Description
ImpactA server can reply with a WebSocket frame using the 64-bit length form and an extremely large length. undici's ByteParser overflows internal math, ends up in an invalid state, and throws a fatal TypeError that terminates the process. Patches Patched in the undici version v7.24.0 and v6.24.0. Users should upgrade to this version or later.
Affected products
nodejs: undici
References10
- cna.openjsf.org/security-advisories.html Vendor Advisory
- github.com/nodejs/undici/security/advisories/GHSA-f269-vfmq-vjvj Vendor Advisory
- hackerone.com/reports/3537648 Permissions Required
- access.redhat.com/errata/RHSA-2026:13826
- access.redhat.com/errata/RHSA-2026:17789
- access.redhat.com/errata/RHSA-2026:21772
- access.redhat.com/errata/RHSA-2026:21931
- access.redhat.com/errata/RHSA-2026:34342
- access.redhat.com/errata/RHSA-2026:5807
- access.redhat.com/errata/RHSA-2026:7080
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 47 · as of 12 November 2026
- CWE
- CWE-248CWE-1284
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.