CVE-2026-85024
undici vulnerable to Denial of Service via unhandled error in WebSocket permessage-deflate decompression
No known exploitation. EPSS puts it in the 33rd percentile. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
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.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.4% chance of exploitation activity in the next 30 days, which ranks it in the 33rd percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
7 events over 12 days, from the signal feeds we watch.
- Patch availablerecord updated
- Record updated
- Publishedweakness classified, record updated, record updated
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Scored 5.9 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity HighRequires specific conditions like a race condition or non-default configuration
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality NoneNo confidentiality impact
- Integrity NoneNo integrity impact
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
Sources
Watch the software you run.
My Stack ranks new CVEs for your products by real-world exploitation, so the next serious one reaches you without reading every advisory.
We'll flag the next CVE, public exploit or patch for Undici, not every advisory.
A free account adds
- The full version matrix and every affected product
- Exploit links, proofs of concept and Metasploit modules
- Email alerts for the products you watch
- The same data over REST API, MCP and CLI