PatchSiren cyber security CVE debrief
CVE-2026-48735 py-pdf CVE debrief
A memory consumption vulnerability exists in pypdf versions prior to 6.12.1. An attacker can craft a PDF with large XMP metadata containing excessive unnecessary elements, causing significant memory usage during parsing. This represents a denial-of-service condition through resource exhaustion. The vulnerability is classified as CWE-770 (Allocation of Resources Without Limits or Throttling). The issue was resolved in pypdf 6.12.1, which implements proper handling of XMP metadata to prevent unbounded memory growth.
- Vendor
- py-pdf
- Product
- pypdf
- CVSS
- MEDIUM 6.9
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-28
- Original CVE updated
- 2026-05-29
- Advisory published
- 2026-05-28
- Advisory updated
- 2026-05-29
Who should care
Organizations using pypdf for PDF processing in server-side applications, document management systems, or automated workflows where untrusted PDFs are ingested. Particularly relevant for services processing user-uploaded documents.
Technical summary
The vulnerability stems from insufficient resource limits when parsing XMP (Extensible Metadata Platform) metadata in PDF files. XMP metadata can contain arbitrarily large XML structures with nested elements. Without proper size constraints or streaming parsing, processing maliciously constructed metadata leads to unbounded memory allocation. The fix in 6.12.1 likely implements parsing limits or streaming processing to bound memory consumption.
Defensive priority
medium
Recommended defensive actions
- Upgrade pypdf to version 6.12.1 or later
- Implement input validation to limit PDF file sizes and metadata complexity before processing
- Monitor memory usage when processing untrusted PDF documents
- Consider sandboxing PDF processing operations with resource limits
- Review applications using pypdf for XMP metadata extraction capabilities
Evidence notes
CVE published 2026-05-28. CVSS 4.0 vector indicates local attack vector with high availability impact. Fix confirmed via GitHub security advisory GHSA-wjqc-6w8f-h24c and release 6.12.1.
Official resources
2026-05-28