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Findings

CVE-2026-1528

ImpactA server can reply with a WebSocket frame using the 64-bit length form and an extremely large length.

Published Mar 12, 2026 · corrected/updated Sep 4, 2026 · Red Hat undici · evidence confidence high

A flaw was found in undici. A remote attacker could exploit this vulnerability by sending a specially crafted WebSocket frame with an extremely large 64-bit length. This causes undici's ByteParser to overflow its internal calculations, leading to an invalid state and a fatal TypeError. The primary consequence is a Denial of Service (DoS), which terminates the process.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-1528 is a high public vulnerability record for Red Hat undici. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether Red Hat undici is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: nodejs/undici. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 7.5, EPSS 0.5%. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-1284, CWE-248. Sources contributing to this record: csaf, cve_org, epss, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 12, 2026 · NIST NVD

    Detected

    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.

  2. Sep 4, 2026 · NIST NVD

    Updated

    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.

Affected

  • cpe nodejs/undiciversion unspecified

Sources

  • CSAF AdvisoriesVendor advisoryRHSA-2026:9742:CVE-2026-1528

    A flaw was found in undici. A remote attacker could exploit this vulnerability by sending a specially crafted WebSocket frame with an extremely large 64-bit length. This causes undici's ByteParser to overflow its internal calculations, leading to an invalid state and a fatal Type

    security.access.redhat.com
  • CVE.orgVulnerability recordCVE-2026-1528

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-1528

    30-day exploitation probability 0.5%

    first.org
  • NIST NVDVulnerability recordCVE-2026-1528

    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

    nvd.nist.gov

References