Excessive Iteration in PyPDF - CVE-2026-48156
Published: May 21, 2026
Vulnerability identifier: #VU132046
CSH Severity: Low
CVSS v4: 5.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-48156
CWE-ID: CWE-834
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to excessive iteration in cross-reference stream processing when parsing a crafted PDF file. A remote attacker can supply a PDF with zero-only width values and a large size value to cause a denial of service.
Exploitation requires cross-reference streams with /W [0 0 0] values and large /Size values.
Affected software
PyPDF
IBM Watson Discovery for IBM Cloud Pak for Data
IBM Watson Discovery for IBM Cloud Pak for Data
How to mitigate CVE-2026-48156
Install security update from vendor's website.
PyPDF - update to 6.12.0
IBM Watson Discovery for IBM Cloud Pak for Data - update to 5.3.2
IBM Watson Discovery for IBM Cloud Pak for Data - update to 5.3.2