CVE-2026-59937
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk27th percentile - higher than 27% of all known CVEs
Summary
In the pypdf library prior to version 6.14.0, a vulnerability allows an attacker to craft a PDF with multiple malformed cross-reference streams, causing long runtimes for recovering broken cross-reference table entries. This leads to excessive CPU usage and processing delays.
Risk Assessment
The risk is a potential Denial of Service (DoS) attack by sending a specially crafted PDF file, which can significantly slow down or hang applications using the pypdf library.
Recommendation
Immediately upgrade pypdf to version 6.14.0 or later, which includes a fix for this vulnerability.
Other vulnerabilities in pypdf
See all- CVE-2026-71870Medium
pypdf prior to 6.15.0 is vulnerable to excessive memory consumption when parsing crafted PDFs, as the parse_bfrange function in pypdf/_cmap.py handles unusually large tokens in a font /ToUnicode CMap during text extraction. This issue is fixed in version 6.15.0.
- CVE-2026-71852Medium
A vulnerability in the pypdf library prior to version 6.15.0 allows long runtimes and high memory consumption when extracting text from a crafted PDF. The Font._collect_cid_character_widths function expands unusually large CID font /W width ranges or excessive width entries. The issue is fixed in version 6.15.0.
- CVE-2026-59936High
In pypdf library prior to version 6.14.1, a vulnerability was found causing an infinite loop when processing inline images in PDF page content streams. An attacker can craft a malicious PDF with a not terminated inline image, leading to a hang during text extraction.
- CVE-2026-59935High
The pypdf library prior to version 6.14.2 is vulnerable to a DoS attack due to an infinite loop when parsing PDF files. An attacker can craft a malicious PDF with a not terminated inline image using ASCII85 or ASCIIHex filters, causing the process to hang.
- CVE-2026-59938Medium
In the pypdf library prior to version 6.14.0, a vulnerability allows an attacker to craft a PDF with declared image size values much larger than the actual data, causing excessive memory usage during image parsing. This can be exploited for a denial-of-service (DoS) attack by exhausting memory resources.
- CVE-2026-57204Medium
The pypdf library before version 6.13.3 contains a DoS vulnerability. A specially crafted PDF can cause excessive memory usage because the MAX_DECLARED_STREAM_LENGTH constant is sometimes ignored when parsing a content stream without a /Length value.
- CVE-2026-54651Medium
pypdf is a free and open-source pure-python PDF library. Prior to version 6.13.1, an attacker could exploit this vulnerability to craft a PDF that leads to an infinite loop.
- CVE-2026-54531Medium
pypdf is a free and open-source pure-python PDF library. Prior to version 6.13.0, an attacker could exploit this vulnerability to craft a PDF that leads to an infinite loop.
- CVE-2026-54530Medium
pypdf is a free and open-source pure-python PDF library. Prior to version 6.13.0, an attacker could exploit this vulnerability to craft a PDF that leads to an infinite loop when extracting text in layout mode.
- CVE-2026-49461Medium
pypdf is a free and open-source pure-python PDF library. Prior to version 6.12.2, an attacker could craft a PDF that leads to large memory usage by extracting text from a page containing a form XObject with self-references.
Original NVD description (English source)
pypdf is a free and open-source pure-python PDF library. Prior to 6.14.0, an attacker can craft a PDF with repeated malformed cross-reference streams that cause pypdf to spend long runtimes recovering broken cross-reference table entries. This issue is fixed in version 6.14.0.

