CVE-2026-85024

Public on 2026-09-04
Modified on 2026-09-05
Description
undici bundles a WebSocket client whose permessage-deflate size-limit cleanup removes all listeners from the internal zlib inflate stream, including its error listener, while that stream can still emit. When a remote peer sends a compressed payload that crosses the built-in 128 MiB decompressed-payload limit and then contains a malformed DEFLATE byte, the inflate stream emits a data error with no listener attached, which Node.js treats as a fatal unhandled error and terminates the entire process. Exploitation is remote and unauthenticated, requires no application mistake, and is asymmetric, since roughly 130 KB on the wire expands past the limit and crashes the process, and reconnecting can repeat the crash. This affects undici versions from 6.25.0 up to 6.28.1, from 7.28.0 up to 7.29.1, and from 8.1.0 up to 8.10.2. Users should upgrade to undici 6.28.1, 7.29.1, or 8.10.2.
Severity
Important severity
Important
See what this means
CVSS v3 Base Score
7.5
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 2023 nodejs No Fix Planned
Amazon Linux 2023 nodejs20 No Fix Planned
Amazon Linux 2023 nodejs22 Pending Fix
Amazon Linux 2023 nodejs24 Pending Fix
Amazon Linux 2027 Preview nodejs24 Pending Fix

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H