Node undici: undici bundles a WebSocket client whose permessage-deflate size-limit cleanup removes all listeners from the internal zlib inflate stream, including… (CVE-2026-85024)
Description
A vulnerability in the undici WebSocket client for Node.js causes the process to crash when processing a specially crafted permessage-deflate compressed message that exceeds the decompressed payload size limit and contains a malformed DEFLATE block. This triggers an unhandled error in the internal zlib InflateRaw stream, leading to process termination. The issue affects undici versions 6.25.0 through before 6.28.1, 7.28.0 through before 7.29.1, and 8.1.0 through before 8.10.2. No workaround is available, but patched versions have been released.
CVSS v3.1
Score 5.9medium
Affected software
pkg:deb/ubuntu/node-undici?arch=source&distro=noblepkg:deb/ubuntu/node-undici?arch=source&distro=resolutepkg:deb/ubuntu/node-undici?arch=source&distro=stonkingRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The undici WebSocket client in Node.js has a vulnerability (CVE-2026-85024) related to its handling of permessage-deflate compressed messages. When a message exceeds the decompressed payload size limit and contains a malformed DEFLATE block, the internal zlib InflateRaw stream emits an unhandled error. This error is not caught, causing the Node.js process to crash. This affects undici versions >=6.25.0 <6.28.1, >=7.28.0 <7.29.1, and >=8.1.0 <8.10.2. The vulnerability results in a denial of service via process termination. Patched versions have been released to address this issue.
Potential Impact
The vulnerability causes a denial of service by crashing the Node.js process running the undici WebSocket client when it receives a maliciously crafted compressed message. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
Patched versions of undici have been released that fix this vulnerability. Users should upgrade to versions 6.28.1 or later, 7.29.1 or later, or 8.10.2 or later. No workaround is available. Applying the official patches is the recommended remediation.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-85024
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:24.04:LTS","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
Threat ID: 6a9ee1aeacd9273b49e69c02
Added to database: 09/07/2026, 16:09:18 UTC
Last enriched: 10/18/2026, 02:24:59 UTC
Last updated: 10/23/2026, 01:15:27 UTC
Views: 80
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