Is this vulnerability remotely exploitable?

Yes. If an application exposes any network-accessible functionality that accepts XML and uses fast-xml-parser, a remote attacker can submit crafted XML payloads to attempt exploitation.

What level of access does an attacker need?

The attacker only needs the ability to influence the XML that the application parses. This could be through public HTTP APIs, partner integrations, uploaded files, or any other input channel that is eventually processed by fast-xml-parser.

What is the safest general fix pattern?

The safest pattern is to use an XML parser configuration where all entity and character reference expansions are consistently limited or disabled unless absolutely necessary, and to treat library-provided limits as advisory rather than your only line of defense. Pair parser-level protections with external request size limits, timeouts, and process isolation, so that even if a specific limit is bypassed, resource exhaustion is constrained.

Severity:

HIGH RISK

(7.5)

XML Entity Expansion DoS (CWE-776) in fast-xml-parser Entity Limits

CVE-2026-33036

Published:

Mar 20, 2026

Status:

Analyzed

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

Recent Vulnerabilities

CWE-918

HIGH RISK

HIGH

(8.6)

Server-Side Request Forgery (CWE-918) in OpenClaw Zalo Plugin sendPhoto

Unauthorized Access to Internal Resources via SSRF

May 6, 2026

CWE-863

HIGH RISK

HIGH

(8.8)

Authorization Bypass (CWE-863) in OpenClaw Matrix Room Control Commands

Privilege Escalation via Bypassed Access Control

May 6, 2026

Vulnerability Type

Category:

XML Entity Expansion Denial of Service

CWE:

CWE-776

Impact:

Denial of Service via uncontrolled resource consumption

Severity:

HIGH RISK

(7.5)

CVSS Version:

3.1

Vulnerability Type

Category:

XML Entity Expansion Denial of Service

CWE:

CWE-776

Impact:

Denial of Service via uncontrolled resource consumption

Severity:

HIGH RISK

(7.5)

CVSS Version:

3.1

Catch This CVE While Code Is Being Written

Detect vulnerable code directly in pull requests, so CVEs are fixed before merge.

Get Started

Ship clean & secure code faster

Start Free Trial

Get Pentest Report

Ship clean & secure code faster

Start Free Trial

Get Pentest Report

Ship clean & secure code faster

Start Free Trial

Get Pentest Report

CodeAnt AI is an offensive and defensive security platform.

Defensive + offensive security.

From first line of code to a pentest
that knows every line of it.

SOC 2 Type II certified | CodeAnt AI is independently audited and compliant with SOC 2 Type II security standards

Ask AI for summary of CodeAnt

Defensive + offensive security.

From first line of code to a pentest
that knows every line of it.

Ask AI for summary of CodeAnt

Defensive + offensive security.

From first line of code to a pentest
that knows every line of it.

Ask AI for summary of CodeAnt

XML Entity Expansion DoS (CWE-776) in fast-xml-parser Entity Limits

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(8.6)

Server-Side Request Forgery (CWE-918) in OpenClaw Zalo Plugin sendPhoto

HIGH RISK

HIGH

(8.8)

Authorization Bypass (CWE-863) in OpenClaw Matrix Room Control Commands

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

Ship clean & secure code faster

Ship clean & secure code faster

Product

Compare

Company

Developers

Legal

Product

Compare

Company

Developers

Legal

Product

Compare

Company

Developers

Legal