CVE-2026-12151
undici WebSocket client vulnerable to denial of service via fragment count bypass
Description
Impact: The undici WebSocket client enforces maxPayloadSize on the cumulative byte count of fragments in a message but does not enforce a limit on the number of fragments. A malicious WebSocket server can stream many small or empty continuation frames that each pass per-frame and cumulative-size validation, collectively causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service. Affected applications are those using the undici WebSocket client (new WebSocket(...)) or the WebSocketStream API that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint. All releases starting at undici 6.17.0 are affected. Patches: Upgrade to undici >= 6.26.0, >= 7.28.0, or >= 8.5.0. Workarounds: No workaround is available. The fix must be applied through an upgrade.
INFO
Published Date :
June 17, 2026, 4:05 p.m.
Last Modified :
June 17, 2026, 4:05 p.m.
Remotely Exploit :
Yes !
Source :
openjs
Affected Products
The following products are affected by CVE-2026-12151
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | ce714d77-add3-4f53-aff5-83d477b104bb |
Solution
- Upgrade undici to version 6.26.0 or later.
- Upgrade undici to version 7.28.0 or later.
- Upgrade undici to version 8.5.0 or later.
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CVE-2026-12151 vulnerability anywhere in the article.