https://cve.radiocsirt.org/rss/recent/all/10 Most recent entries from all 2026-10-09T13:37:48.202536+00:00 Vulnerability-Lookup csirt@opendfir.org python-feedgen Contains only the most 10 recent entries. https://cve.radiocsirt.org/vuln/cve-2023-36807 CVE-2023-36807 — Infinite Loop when reading malformed objects in pypdf 2026-10-09T13:37:48.204259+00:00

Affected: py-pdf pypdf, pypdf_project pypdf

pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. In version 2.10.5 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 a malformed PDF. Versions prior to 2.10.5 throw an error, but do not hang forever. This issue was fixed with https://github.com/py-pdf/pypdf/pull/1331 which has been included in release 2.10.6. Users are advised to upgrade. Users unable to upgrade should modify `PyPDF2/generic/_data_structures.py::read_object` to an an error throwing case. See GHSA-hm9v-vj3r-r55m for details.

 https://cve.radiocsirt.org/vuln/ghsa-hm9v-vj3r-r55m GHSA-hm9v-vj3r-r55m — PyPDF2 vulnerable to possible Infinite Loop when reading malformed objects 2026-10-09T13:37:48.204315+00:00

Affected: PyPI: PyPDF2

### 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 a malformed PDF.

### Patches The issue was fixed with https://github.com/py-pdf/pypdf/pull/1331

### Workarounds If you cannot update your version of `PyPDF2` (preferably to `pypdf>3.1.0` as PyPDF2 is deprecated), you should modify `PyPDF2/generic/_data_structures.py::read_object`.

Replace:

```python else: # number object OR indirect reference peek = stream.read(20) stream.seek(-len(peek), 1) # reset to start if IndirectPattern.match(peek) is not None: return IndirectObject.read_from_stream(stream, pdf) else: return NumberObject.read_from_stream(stream) ```

by

```python elif tok in b"0123456789+-.": # number object OR indirect reference peek = stream.read(20) stream.seek(-len(peek), 1) # reset to start if IndirectPattern.match(peek) is not None: return IndirectObject.read_from_stream(stream, pdf) else: return NumberObject.read_from_stream(stream) else: raise PdfReadError( f"Invalid Elementary Object starting with {tok} @{stream.tell()}" ) ```

### References * [pypdf issue #1329](https://github.com/py-pdf/py…