What is the CVSS score of CVE-2026-1528?

CVE-2026-1528 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.1%.

How to fix or mitigate CVE-2026-1528?

Within 24 hours: Inventory all systems using undici library and assess WebSocket exposure. Within 7 days: Implement network-level controls to restrict WebSocket traffic and deploy monitoring for abnormal frame sizes; contact undici maintainers for patch timeline. Within 30 days: Migrate to patched version immediately upon release, or evaluate alternative HTTP client libraries if patch is delayed.

Undici CVE-2026-1528

Q: Which versions of Undici are affected by CVE-2026-1528?

CVE-2026-1528 affects applications using the undici HTTP client library, where attackers can crash servers by sending specially crafted WebSocket frames, causing service disruption.. A patch is available.

EUVD-2026-11703 HIGH

Uncaught Exception (CWE-248)

2026-03-12 ce714d77-add3-4f53-aff5-83d477b104bb

GHSA-f269-vfmq-vjvj

Buffer Overflow Node.js Undici

7.5

CVSS 3.1 · Vendor: ce714d77-add3-4f53-aff5-83d477b104bb

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Send WebSocket frame with 64-bit length form
Exploit

Specify extremely large length value
Execution

Trigger integer overflow in ByteParser
Impact

Process terminates with fatal TypeError

Vulnerability Assessment

Weakness	CWE CWE-248 OWASP Top 10:2025 A10:2025 - Mishandling of Exceptional Conditions ASVS 5.0 V16 - Security Logging and Error Handling Exception handling completeness
Exploitation Conditions	No special conditions — remote unauthenticated exploitation against undici versions prior to v7.24.0 or v6.24.0 accepting WebSocket connections.
Impact	CVSS 7.5 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None.
Exploit ScenarioDerived	An attacker could exploit this vulnerability to compromise the affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Undici's WebSocket frame parser fails to properly validate 64-bit length fields, causing integer overflow in internal calculations that leaves the parser in an invalid state and crashes the process with a fatal TypeError. An unauthenticated remote attacker can exploit this to achieve denial of service by sending a specially crafted WebSocket frame. Versions 7.24.0, 6.24.0, and later contain fixes for this vulnerability.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 22:55 CVSS 7.5

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. [CVSS 7.5 HIGH]

RemediationAI

Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.

Affected VersionsENISA

undici 6.0.0 < 6.24.0; 7.0.0 < 7.24.0

Affected Packages

npm undici fix: 6.24.0, 7.24.0

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in npm

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Patches

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

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (ce714d77-add3-4f53-aff5-83d477b104bb) PRIMARY 7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SUSE HIGH

Red Hat 7.5 HIGH

Primary rating from Vendor (ce714d77-add3-4f53-aff5-83d477b104bb).

CVSS VectorVendor: ce714d77-add3-4f53-aff5-83d477b104bb

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

CVE Published

Mar 12, 2026 - 21:16 nvd

HIGH 7.5

DescriptionCVE.org

Patches

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

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

1 npm packages depend on undici (1 direct, 0 indirect)

Ecosystem-wide dependent count for version 6.0.0.

Executive ViewAI

Why It Matters

CVE-2026-1528 affects applications using the undici HTTP client library, where attackers can crash servers by sending specially crafted WebSocket frames, causing service disruption. This vulnerability poses availability risk to any services relying on undici for WebSocket communication, potentially impacting customer-facing applications and internal integrations.

Business Impact: High

Compensating Controls

Implement Web Application Firewall (WAF) rules to detect and block WebSocket frames with suspicious 64-bit length encoding; deploy network segmentation to limit WebSocket endpoint exposure; configure connection timeouts and rate limiting on WebSocket handlers; monitor for sudden process terminations and implement auto-restart mechanisms; disable WebSocket functionality if not business-critical until patch availability.

Threat Intelligence Overview

EPSS Score

0.1%

Top 83% exploitable

Data Quality

7 sources

Confidence: High

EUVD

NVD

CVE.org

EPSS Vendor

GitHub

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 0.1%

Patch available Yes

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +38

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.