PT-2026-56527

Name of the Vulnerable Software and Affected Versions pypdf versions prior to 6.14.0 Description An attacker can craft a PDF containing repeated malformed cross-reference streams. This causes the library to spend excessive runtimes attempting to recover broken cross-reference table entries, leadi...

CVE-2026-59938: Memory Allocation with Excessive Size Value

pypdf is a free and open-source pure-python PDF library. Prior to 6.14.0, an attacker can craft a PDF with declared image size values that are much too large compared to the actual data, causing large memory usage in pypdf image parsing. This issue is fixed in version 6.14.0...

PYSEC-2026-1827 pypdf has possible Infinite Loop when processing outlines/bookmarks

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires accessing the outlines/bookmarks. Patches This has been fixed in pypdf 6.6.2. Workarounds If projects cannot upgrade yet, consider applying the changes from PR 3610...

pypdf has possible long runtimes for missing /Root object with large /Size values

ImpactAn attacker who exploits this vulnerability can craft a PDF which leads to possibly long runtimes for actually invalid files. This can be achieved by omitting the /Root entry in the trailer, while using a rather large /Size value. Only the non-strict reading mode is affected. PatchesThis ha...

pypdf has possible long runtimes for malformed startxref

ImpactAn attacker who exploits this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading mode is affected...

PYSEC-2026-1828 pypdf has possible long runtimes for malformed startxref

Impact An attacker who exploits this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading mode is affected. Patches...

PYSEC-2026-1832 pypdf's LZWDecode streams be manipulated to exhaust RAM

Impact An attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter. This is a follow up to GHSA-jfx9-29x2-rv3j to align the default limit with the one for zlib. Patche...

pypdf possibly loops infinitely when reading DCT inline images without EOF marker

ImpactAn attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires parsing the content stream of a page which has an inline image using the DCTDecode filter. PatchesThis has been fixed in pypdf==6.1.3. WorkaroundsIf you cannot upgrade yet, consider applyi...

PYSEC-2026-1833 pypdf possibly loops infinitely when reading DCT inline images without EOF marker

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires parsing the content stream of a page which has an inline image using the DCTDecode filter. Patches This has been fixed in pypdf==6.1.3. Workarounds If you cannot upgrade yet, consider...

PYSEC-2026-1831 pypdf can exhaust RAM via manipulated LZWDecode streams

Impact An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing the content stream of a page using the LZWDecode filter. Patches This has been fixed in pypdf==6.1.3. Workarounds If you cannot upgrade yet, consider applying the changes from P...

PYSEC-2026-1830 PyPDF's Manipulated FlateDecode streams can exhaust RAM

Impact An attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires just reading the file if a series of FlateDecode filters is used on a malicious cross-reference stream. Other content streams are affected on explicit access. Patches This has been...

PYSEC-2026-1834 Possible Infinite Loop when PdfWriter(clone_from) is used with a PDF

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case when the pypdf-user manipulates an incomi...

PYSEC-2026-1836 PyPDF2 vulnerable to possible Infinite Loop when reading malformed objects

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if the user extracted metadata from such ...

PYSEC-2026-1835 pypdf and PyPDF2 possible Infinite Loop when a comment isn't followed by a character

Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop if parsecontentstream is executed. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if the...

PyPDF2 vulnerable to possible Infinite Loop when reading malformed objects

ImpactAn attacker who uses this vulnerability can craft a PDF which leads to an infinite loop.This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if the user extracted metadata from such a...

PyPDF2 quadratic runtime with malformed PDF missing xref marker

ImpactAn attacker who uses this vulnerability can craft a PDF which leads to unexpected long runtime.This quadratic runtime blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. Patcheshttps://github.com/py-pdf/pypdf/pull/808 WorkaroundsIs...

pypdf and PyPDF2 possible Infinite Loop when a comment isn't followed by a character

ImpactAn attacker who uses this vulnerability can craft a PDF which leads to an infinite loop if parsecontentstream is executed. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if the...

Linux Distros Unpatched Vulnerability : CVE-2026-57204

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can...

CVE-2026-57204

A flaw was found in pypdf, a pure-python PDF library. A remote attacker could exploit this vulnerability by crafting a malicious PDF file that, when parsed, leads to uncontrolled resource consumption and large memory usage. This occurs because the library sometimes ignores defined limits for stre...

DEBIAN-CVE-2026-57204

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.3, a maliciously crafted PDF can cause DoS. An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAXDECLAREDSTREAMLENGTH is sometimes ignored. This requires parsing a content stream...