CVE-2026-1528: undici is vulnerable to Malicious WebSocket 64-bit length overflows undici parser and crashes the client

Published Mar 12, 2026
·
Updated

Impact A server can reply with a WebSocket frame using the 64-bit length form and an extremely large length. undici's ByteParser overflows internal math, ends up in an invalid state, and throws a fatal TypeError that terminates the process.

Patches

Patched in the undici version v7.24.0 and v6.24.0. Users should upgrade to this version or later.

Workarounds

There are no workarounds.

Other sources

ImpactA server can reply with a WebSocket frame using the 64-bit length form and an extremely large length. undici's ByteParser overflows internal math, ends up in an invalid state, and throws a fatal TypeError that terminates the process.

Patches

Patched in the undici version v7.24.0 and v6.24.0. Users should upgrade to this version or later.

— MITRE

Affected Software

6 affected componentsFixes available
npm/undici<7.24.0, <6.24.0
npm/undici>=7.0.0<7.24.0
7.24.0
npm/undici>=6.0.0<6.24.0
6.24.0
Nodejs Undici Node.js<6.24.0
Nodejs Undici Node.js>=7.0.0<7.24.0
IBM watsonx.data intelligence<=5.2.0, 5.2.1, 5.3.0, 5.3.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade npm/undici to a version that resolves this vulnerability.

    Fixed in 7.24.0
  2. Upgrade

    Upgrade npm/undici to a version that resolves this vulnerability.

    Fixed in 6.24.0
  3. Upgrade

    Upgrade undici to a version that resolves this vulnerability.

    Fixed in 7.24.0
  4. Upgrade

    Upgrade undici to a version that resolves this vulnerability.

    Fixed in 6.24.0

Event History

Mar 12, 2026
CVE Published
via MITRE·08:21 PM
Data Sourced
via MITRE·08:21 PM
DescriptionSeverityWeakness
Data Sourced
via Red Hat·09:02 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·09:16 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·09:16 PM
Affected Software
Mar 13, 2026
Advisory Published
via GitHub·08:07 PM
Data Sourced
via GitHub·08:07 PM
DescriptionSeverityWeaknessAffected Software
Apr 27, 2026
Data Sourced
via IBM·12:00 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2026-1528?

CVE-2026-1528 has a high severity rating due to the potential for crashes and disruption of client operations.

2

How do I fix CVE-2026-1528?

To fix CVE-2026-1528, upgrade to undici version 7.24.1 or later, or 6.24.1 or later.

3

What versions of undici are affected by CVE-2026-1528?

CVE-2026-1528 affects undici versions up to 6.24.0 and 7.24.0 exclusively.

4

What impact does CVE-2026-1528 have on applications?

CVE-2026-1528 can cause the client to crash if a malicious WebSocket frame with a large length is processed.

5

Is CVE-2026-1528 related to WebSocket behavior?

Yes, CVE-2026-1528 arises from the handling of 64-bit length fields in WebSocket frames by the undici parser.

Company

Resources

Contact

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