Withdrawn by the publisher.

Affected: CleanStart: mongosh

Multiple security vulnerabilities affect the mongosh package. These issues are resolved in later releases. See references for individual vulnerability details.

fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. Versions 4.0.0-beta.3 through 5.5.5 contain a bypass vulnerability where numeric character references (&#NNN;, &#xHH;) and standard XML entities completely evade the entity expansion limits (e.g., maxTotalExpansions, maxExpandedLength) added to fix CVE-2026-26278, enabling XML entity expansion Denial of Service. The root cause is that replaceEntitiesValue() in OrderedObjParser.js only enforces expansion counting on DOCTYPE-defined entities while the lastEntities loop handling numeric/standard entities performs no counting at all. An attacker supplying 1M numeric entity references like A can force ~147MB of memory allocation and heavy CPU usage, potentially crashing the process—even when developers have configured strict limits. This issue has been fixed in version 5.5.6.

Affected: npm: fast-xml-parser

## Summary

The fix for CVE-2026-26278 added entity expansion limits (`maxTotalExpansions`, `maxExpandedLength`, `maxEntityCount`, `maxEntitySize`) to prevent XML entity expansion Denial of Service. However, these limits are only enforced for DOCTYPE-defined entities. **Numeric character references** (`&#NNN;` and `&#xHH;`) and standard XML entities (`<`, `>`, etc.) are processed through a separate code path that does NOT enforce any expansion limits.

An attacker can use massive numbers of numeric entity references to completely bypass all configured limits, causing excessive memory allocation and CPU consumption.

## Affected Versions

fast-xml-parser v5.x through v5.5.3 (and likely v5.5.5 on npm)

## Root Cause

In `src/xmlparser/OrderedObjParser.js`, the `replaceEntitiesValue()` function has two separate entity replacement loops:

1. **Lines 638-670**: DOCTYPE entities — expansion counting with `entityExpansionCount` and `currentExpandedLength` tracking. This was the CVE-2026-26278 fix. 2. **Lines 674-677**: `lastEntities` loop — replaces standard entities including `num_dec` (`/&#([0-9]{1,7});/g`) and `num_hex` (`/&#x([0-9a-fA-F]{1,6});/g`). **This loop has NO expansion counting at all.**

The numeric entity regex replacements at lines 97-98 are part of `lastEntities` and go through the uncounted loop, completely bypassing the CVE-2026-26278 fix.

## Proof of Concept

```javascript const { XMLParser } = require('fast-xml-parser');

// Even with strict explicit lim…

heroic-games-launcher-2.20.1-4.1 on GA media

lodash: lodash: Arbitrary code execution via untrusted input in template imports fast-xml-parser: fast-xml-parser: Stack overflow leads to Denial of Service fast-xml-parser: fast-xml-parser: Denial of Service via XML entity expansion bypass google.golang.org/grpc/grpc-go: google.golang.org/grpc/authz: gRPC-Go: Authorization bypass due to improper HTTP/2 path validation github.com/go-jose/go-jose/v3: github.com/go-jose/go-jose/v4: Go JOSE: Denial of Service via crafted JSON Web Encryption (JWE) object

Affected: Ubuntu:24.04:LTS: node-webfont, Ubuntu:25.10: node-webfont, Ubuntu:26.04:LTS: node-webfont

fast-xml-parser allows users to process XML from JS object without C/C++ based libraries or callbacks. Versions 4.0.0-beta.3 through 5.5.5 contain a bypass vulnerability where numeric character references (&#NNN;, &#xHH;) and standard XML entities completely evade the entity expansion limits (e.g., maxTotalExpansions, maxExpandedLength) added to fix CVE-2026-26278, enabling XML entity expansion Denial of Service. The root cause is that replaceEntitiesValue() in OrderedObjParser.js only enforces expansion counting on DOCTYPE-defined entities while the lastEntities loop handling numeric/standard entities performs no counting at all. An attacker supplying 1M numeric entity references like A can force ~147MB of memory allocation and heavy CPU usage, potentially crashing the process—even when developers have configured strict limits. This issue has been fixed in version 5.5.6.

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise ausnutzen, um Dateien zu manipulieren, und um einen Denial of Service Angriff durchzuführen.