XML External Entity injection in pikepdf - CVE-2021-29421
Published: April 12, 2021
Vulnerability identifier: #VU52044
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-29421
CWE-ID: CWE-611
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to gain access to sensitive information.
The vulnerability exists due to insufficient validation of user-supplied XML input in models/metadata.py when parsing XMP metadata entries. A remote attacker can pass a specially crafted XML code to the affected application and view contents of arbitrary files on the system or initiate requests to external systems.
Successful exploitation of the vulnerability may allow an attacker to view contents of arbitrary file on the server or perform network scanning of internal and external infrastructure.
Affected software
pikepdf
Fedora
python-pikepdf
Fedora
python-pikepdf
How to mitigate CVE-2021-29421
Install updates from vendor's website.
pikepdf - update to 2.10.0
python-pikepdf - addressed in versions 1.19.4-2.fc32, 1.19.4-2.fc33
python-pikepdf - addressed in versions 1.19.4-2.fc32, 1.19.4-2.fc33
External References
- https://github.com/pikepdf/pikepdf/commit/3f38f73218e5e782fe411ccbb3b44a793c0b343a
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/36P4HTLBJPO524WMQWW57N3QRF4RFSJG/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3QFLBBYGEDNXJ7FS6PIWTVI4T4BUPGEQ/