CVE-2026-27025

pypdf has possible long runtimes/large memory usage for large /ToUnicode streams

pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes and large memory consumption. This requires parsing the /ToUnicode entry of a font with unusually large values, for example during text extraction. This vulnerability is fixed in 6.7.1.

CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-27026

pypdf possibly has long runtimes for malformed FlateDecode streams

pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a malformed /FlateDecode stream, where the byte-by-byte decompression is used. This vulnerability is fixed in 6.7.1.

CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-28804

pypdf: Inefficient decoding of ASCIIHexDecode streams

pypdf is a free and open-source pure-python PDF library. Prior to version 6.7.5, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires accessing a stream which uses the /ASCIIHexDecode filter. This issue has been patched in version 6.7.5.

CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-41168

pypdf has possible long runtimes for wrong size values in cross-reference and object streams

pypdf is a free and open-source pure-python PDF library. An attacker who uses a vulnerability present in versions prior to 6.10.1 can craft a PDF which leads to long runtimes. This requires cross-reference streams with wrong large `/Size` values or object streams with wrong large `/N` values. This has been fixed in pypdf 6.10.1. As a workaround, one may apply the changes from the patch manually.

CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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Py-pdf Pypdf Project

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Pypdf Pypdf

CVE-2026-48735

pypdf: Manipulated XMP metadata streams can exhaust RAM

pypdf is a free and open-source pure-python PDF library. Prior to 6.12.1, an attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing large XMP metadata, possibly with lots of unnecessary elements. This vulnerability is fixed in 6.12.1.

CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-54531

pypdf: Possible infinite loop when processing outlines/bookmarks in writer

pypdf is a free and open-source pure-python PDF library. Prior to 6.13.0, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with outlines into a writer. This vulnerability is fixed in 6.13.0.

CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-57204

pypdf: Missing stream length values ignore defined limits

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 MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value. This issue has been fixed in version 6.13.3.

CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-59937

pypdf: Possible long runtimes for repeated malformed cross-reference entries

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.

CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-71852

pypdf: Possible long runtimes/large memory usage for large CID font width ranges

pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, a crafted PDF can cause long runtimes and large memory consumption when pypdf/_font.py function Font._collect_cid_character_widths expands unusually large CID font /W width ranges or excessive width entries during text extraction. This issue is fixed in 6.15.0.

CVSS 4.0 · 4.8 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-82398

pypdf: Inefficient handling of non-whitespace inputs in read_until_whitespace

pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.

CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-84309

pypdf: Possible infinite loop for TreeObject.insert_child

pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.

CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-84310

pypdf: Possible long runtimes/large memory usage when retrieving outlines

pypdf is a free and open-source pure-python PDF library. Prior to 6.16.1, an attacker can craft a PDF that causes pypdf/_doc_common.py _get_outline to consume long runtimes and large amounts of memory when retrieving document outlines with large numbers of entries or deeply nested reused paths because the traversal lacked global entry-count and nesting-depth limits. This issue is fixed in version 6.16.1.

CVSS 4.0 · 4.8 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-84311

pypdf: Possible long runtimes/large memory usage when extracting XForm objects

pypdf is a free and open-source pure-python PDF library. Prior to 6.16.1, an attacker can craft a PDF that causes pypdf/_page.py PageObject._extract_text and PageObject.extract_xform_text to traverse a directed acyclic graph of reused form XObjects in which each form invokes a child multiple times, creating exponentially many traversal paths and causing long runtimes and large memory consumption. This issue is fixed in version 6.16.1.

CVSS 4.0 · 4.8 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2025-55197

pypdf's Manipulated FlateDecode streams can exhaust RAM

pypdf is a free and open-source pure-python PDF library. Prior to version 6.0.0, an attacker 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. This issue has been fixed in 6.0.0. If an update is not possible, a workaround involves including the fixed code from pypdf.filters.decompress into the existing filters file.

CVSS 4.0 · 6.6 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-119205

pypdf: Possible infinite loop when cloning dictionaries

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.4, pypdf can enter an infinite loop when cloning or duplicating a crafted cyclic DictionaryObject. Clone traversal checked generated destination references rather than the original source references, allowing some source cycles to evade the visited-object check. This issue is fixed in version 6.21.4.

CVSS 4.0 · 7.1 High EPSS < 1% KEV · Not listed

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Py-pdf

Products

Pypdf

CVE-2026-119207

pypdf: Possible large memory usage for exceptions in strict mode

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.3, pypdf can consume excessive memory when strict mode loads a crafted invalid PDF dictionary. Nested parsing failures add repeated exception text to newly raised errors, allowing a small malformed dictionary to amplify into very large error messages. This issue is fixed in version 6.21.3.

CVSS 4.0 · 7.1 High EPSS < 1% KEV · Not listed

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Py-pdf

Products

Pypdf

CVE-2026-48155

pypdf: Possible large memory usage for large offsets for layout mode text

pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires extracting text in layout mode with large character offsets. This vulnerability is fixed in 6.12.0.

CVSS 4.0 · 4.8 Medium EPSS < 1% KEV · Not listed

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Py-pdf

Products

Pypdf

CVE-2026-48156

pypdf: Possible long runtimes for zero-only width values in cross-reference streams

pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with /W [0 0 0] values and large /Size values. This vulnerability is fixed in 6.12.0.

CVSS 4.0 · 5.1 Medium EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-59935

pypdf: Possible infinite loop for not terminated inline images (ASCII85 and ASCIIHex filter)

pypdf is a free and open-source pure-python PDF library. Prior to 6.14.2, an attacker can craft a PDF with a page content stream containing a not terminated inline image that uses the ASCII85 or ASCIIHex filters, causing an infinite loop during parsing such as when extracting page text. This issue is fixed in version 6.14.2.

CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf

CVE-2026-59936

pypdf: Possible infinite loop for not terminated inline images

pypdf is a free and open-source pure-python PDF library. Prior to 6.14.1, an attacker can craft a PDF with a page content stream containing a not terminated inline image, causing an infinite loop during inline image end marker detection such as when extracting page text. This issue is fixed in version 6.14.1.

CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed

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Py-pdf

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Pypdf