GHSA-432c-wxpg-m4q3 xml2rfc has file inclusion irregularities
Attackers can read arbitrary files within the source directory via artwork or sourcecode elements, bypassing local file access restrictions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is GHSA-432c-wxpg-m4q3?
GHSA-432c-wxpg-m4q3 is a path traversal vulnerability in xml2rfc, published on 7 Feb 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Version 3.12.0 changed xml2rfc so that it would not access local files without the presence of its new --allow-local-file-access flag.
This prevented XML External Entity (XXE) injection attacks with xinclude and XML entity references.
It was discovered that xml2rfc does not respect --allow-local-file-access when a local file is specified as src in artwork or sourcecode elements. Furthermore, XML entity references can include any file inside the source dir and below without using the --allow-local-file-access flag.
The xml2rfc <= 3.26.0 behaviour:
xinclude | XML entity reference | artwork src= | sourcecode src= | |
|---|---|---|---|---|
without --allow-local-file-access flag | No filesystem access | Any file in xml2rfc templates dir and below, any file in source directory and below | Access source directory and below | Access source directory and below |
with --allow-local-file-access flag | Access any file on filesystem1 | Access any file on filesystem1 | Access source directory and below | Access source directory and below |
Impact
Anyone running xml2rfc as a service that accepts input from external users is impacted by this issue.
Specifying a file in src attribute in artwork or sourcecode elements will cause the contents of that file to appear in xml2rfc’s output results.
But that file has to be inside the same directory as the XML input source file.
For artwork and sourcecode, xml2rfc will not look above the source file directory.
The proposed new behaviour
- Generalize file access checks.
- Only allow access to files within src dir and below. (xml entity include can access templates dir).
- Always allow access to
templates_dirfor XML entity includes.
New behaviour:
xinclude | XML entity reference | artwork src= | sourcecode src= | |
|---|---|---|---|---|
without --allow-local-file-access flag | No filesystem access | No filesystem access (except for templates_dir) | No filesystem access | No filesystem access |
with --allow-local-file-access flag | Access source directory and below | Access source directory and below (Can accesstemplates_dir). | Access source directory and below | Access source directory and below |
Workarounds
Use a secure temporary directory to process un-trusted XML files, and do not reuse it for processing other XML documents.
Which versions are affected by GHSA-432c-wxpg-m4q3?
2 open source packages ship an affected version, including xml2rfc.
| Package | Affected | Fixed in |
|---|---|---|
xml2rfc PyPI | From 3.12.0 | 3.27.0 |
xml2rfc PyPI | From 3.12.0 | 3.27.0 |
How do I fix GHSA-432c-wxpg-m4q3?
Upgrade xml2rfc to 3.27.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is GHSA-432c-wxpg-m4q3 being exploited?
There is no known exploitation of GHSA-432c-wxpg-m4q3 in the wild and no public exploit code.