Withdrawn by the publisher.

Affected: CleanStart: renovate

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

fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. From 4.1.3to before 5.3.5, a dot (.) in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow built-in XML entities (<, >, &, ", ') with arbitrary values. This bypasses entity encoding and leads to XSS when parsed output is rendered. This vulnerability is fixed in 5.3.5.

Affected: npm: fast-xml-parser

# Entity encoding bypass via regex injection in DOCTYPE entity names

## Summary

A dot (`.`) in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow built-in XML entities (`<`, `>`, `&`, `"`, `'`) with arbitrary values. This bypasses entity encoding and leads to XSS when parsed output is rendered.

## Details

The fix for CVE-2023-34104 addressed some regex metacharacters in entity names but missed `.` (period), which is valid in XML names per the W3C spec.

In `DocTypeReader.js`, entity names are passed directly to `RegExp()`:

```js entities[entityName] = { regx: RegExp(`&${entityName};`, "g"), val: val }; ```

An entity named `l.` produces the regex `/&l.;/g` where `.` matches **any character**, including the `t` in `<`. Since DOCTYPE entities are replaced before built-in entities, this shadows `<` entirely.

The same issue exists in `OrderedObjParser.js:81` (`addExternalEntities`), and in the v6 codebase - `EntitiesParser.js` has a `validateEntityName` function with a character blacklist, but `.` is not included:

```js // v6 EntitiesParser.js line 96 const specialChar = "!?\\/[]$%{}^&*()<>|+"; // no dot ```

## Shadowing all 5 built-in entities

| Entity name | Regex created | Shadows | |---|---|---| | `l.` | `/&l.;/g` | `&lt;` | | `g.` | `/&g.;/g` | `&gt;` | | `am.` | `/&am.;/g` | `&amp;` | | `quo.` | `/&quo.;/g` | `&quot;` | | `apo.` | `/&apo.;/g` | `&apos;` |

## PoC

```js…

node-forge: node-forge: Interpretation conflict vulnerability allows bypassing cryptographic verifications lodash: prototype pollution in _.unset and _.omit functions qs: qs: Denial of Service via improper input validation in array parsing node-forge: node-forge ASN.1 Unbounded Recursion webpack: webpack buildHttp HttpUriPlugin allowedUris bypass via HTTP redirects webpack: webpack buildHttp: allowedUris allow-list bypass via URL userinfo (@) leading to build-time SSRF behavior ajv: ReDoS via $data reference lodash: lodash: Arbitrary code execution via untrusted input in template imports @remix-run/router: react-router: React Router vulnerable to XSS via Open Redirects fast-xml-parser: fast-xml-parser has RangeError DoS Numeric Entities Bug fast-xml-parser: fast-xml-parser: Cross-Site Scripting (XSS) due to improper DOCTYPE entity handling fast-xml-parser: fast-xml-parser: Denial of Service via unlimited XML entity expansion minimatch: minimatch: Denial of Service via specially crafted glob patterns minimatch: Minimatch: Denial of Service via catastrophic backtracking in glob expressions fast-xml-parser: fast-xml-parser: Stack overflow leads to Denial of Service immutable-js: Immutable.js: Arbitrary code execution via Prototype Pollution 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/jackc/pgx/v5: g…

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

fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. From 4.1.3to before 5.3.5, a dot (.) in a DOCTYPE entity name is treated as a regex wildcard during entity replacement, allowing an attacker to shadow built-in XML entities (&lt;, &gt;, &amp;, &quot;, &apos;) with arbitrary values. This bypasses entity encoding and leads to XSS when parsed output is rendered. This vulnerability is fixed in 5.3.5.

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise ausnutzen, um einen Denial-of-Service-Zustand herbeizuführen oder Sicherheitsmaßnahmen zu umgehen, wodurch Cross-Site-Scripting-Angriffe ermöglicht werden.