Headline
CVE-2023-27476: XML External Entity (XXE) Injection in OWSLib
OWSLib is a Python package for client programming with Open Geospatial Consortium (OGC) web service interface standards, and their related content models. OWSLib’s XML parser (which supports both lxml and xml.etree) does not disable entity resolution, and could lead to arbitrary file reads from an attacker-controlled XML payload. This affects all XML parsing in the codebase. This issue has been addressed in version 0.28.1. All users are advised to upgrade. The only known workaround is to patch the library manually. See GHSA-8h9c-r582-mggc for details.
Impact
OWSLib’s XML parser (which supports both lxml and xml.etree) does not disable entity resolution, and could lead to arbitrary file reads from an attacker-controlled XML payload. This affects all XML parsing in the codebase.
Patches
- Use only lxml for XML handling: #863
Workarounds
The patch approach should be:
- update all XML support as follows:
- use ONLY lxml.etree
- apply the patch below
patch_well_known_namespaces(etree) etree.set_default_parser( parser=etree.XMLParser(resolve_entities=False) )
References
- GHSL-2022-131
Related news
Debian Linux Security Advisory 5426-1 - An arbitrary file reads from malformed XML payload vulnerability was discovered in owslib, the Python client library for Open Geospatial (OGC) web services. This issue has been addressed by always using lxml as the XML parser with entity resolution disabled.
### Impact OWSLib's XML parser (which supports both `lxml` and `xml.etree`) does not disable entity resolution, and could lead to arbitrary file reads from an attacker-controlled XML payload. This affects all XML parsing in the codebase. ### Patches This issue is patched in 0.28.1. ### Workarounds The patch approach should be: - update all XML support as follows: - use ONLY `lxml.etree` - apply the patch below ```python patch_well_known_namespaces(etree) etree.set_default_parser( parser=etree.XMLParser(resolve_entities=False) ) ``` ### References - `GHSL-2022-131`