Detections
Analytics
CVE-2026-1526
high
Description
The undici WebSocket client is vulnerable to a denial-of-service attack via unbounded memory consumption during permessage-deflate decompression. When a WebSocket connection negotiates the permessage-deflate extension, the client decompresses incoming compressed frames without enforcing any limit on the decompressed data size. A malicious WebSocket server can send a small compressed frame (a "decompression bomb") that expands to an extremely large size in memory, causing the Node.js process to exhaust available memory and crash or become unresponsive. The vulnerability exists in the PerMessageDeflate.decompress() method, which accumulates all decompressed chunks in memory and concatenates them into a single Buffer without checking whether the total size exceeds a safe threshold.
References
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-1526.json
https://hackerone.com/reports/3481206
https://github.com/nodejs/undici/security/advisories/GHSA-vrm6-8vpv-qv8q
https://datatracker.ietf.org/doc/html/rfc7692
https://cna.openjsf.org/security-advisories.html
https://bugzilla.redhat.com/show_bug.cgi?id=2447142
https://access.redhat.com/security/cve/CVE-2026-1526
https://access.redhat.com/errata/RHSA-2026:9742
https://access.redhat.com/errata/RHSA-2026:7983
https://access.redhat.com/errata/RHSA-2026:7675
https://access.redhat.com/errata/RHSA-2026:7670
https://access.redhat.com/errata/RHSA-2026:7350
https://access.redhat.com/errata/RHSA-2026:7310
https://access.redhat.com/errata/RHSA-2026:7302
https://access.redhat.com/errata/RHSA-2026:7123
https://access.redhat.com/errata/RHSA-2026:7080
https://access.redhat.com/errata/RHSA-2026:5807
https://access.redhat.com/errata/RHSA-2026:34342
https://access.redhat.com/errata/RHSA-2026:21931
https://access.redhat.com/errata/RHSA-2026:21772