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 __parse_content_stream 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 user extracted text from such a PDF.
Example Code and a PDF that causes the issue:
from pypdf import PdfReader
# https://objects.githubusercontent.com/github-production-repository-file-5c1aeb/3119517/11367871?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20230627%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20230627T201018Z&X-Amz-Expires=300&X-Amz-Signature=d71c8fd9181c4875f0c04d563b6d32f1d4da6e7b2e6be2f14479ce4ecdc9c8b2&X-Amz-SignedHeaders=host&actor_id=1658117&key_id=0&repo_id=3119517&response-content-disposition=attachment%3Bfilename%3DMiFO_LFO_FEIS_NOA_Published.3.pdf&response-content-type=application%2Fpdf
reader = PdfReader("MiFO_LFO_FEIS_NOA_Published.3.pdf")
page = reader.pages[0]
page.extract_text()The issue was introduced with https://github.com/py-pdf/pypdf/pull/969
Patches
The issue was fixed with https://github.com/py-pdf/pypdf/pull/1828
Workarounds
It is recommended to upgrade to pypdf>=3.9.0. PyPDF2 users should migrate to pypdf.
If you cannot update your version of pypdf, you should modify pypdf/generic/_data_structures.py:
OLD: while peek not in (b"\r", b"\n"):
NEW: while peek not in (b"\r", b"\n", b""):Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | pypdf | >= 3.1.0, < 3.9.0 | 3.9.0 |
| Python (PyPI) | pypdf2 | >= 2.2.0, <= 3.0.1 | sin corrección |
Referencias
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-4vvm-4w3v-6mr8
- https://nvd.nist.gov/vuln/detail/CVE-2023-36464
- https://github.com/py-pdf/pypdf/pull/1828
- https://github.com/py-pdf/pypdf/pull/969
- https://github.com/py-pdf/pypdf/commit/b0e5c689df689ab173df84dacd77b6fc3c161932
- https://github.com/py-pdf/pypdf
- https://github.com/py-pdf/pypdf/releases/tag/3.9.0
- https://pypi.org/project/pypdf2
- https://github.com/advisories/GHSA-4vvm-4w3v-6mr8
- https://pypi.org/project/pypdf
- Vector CVSS
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Debilidad (CWE)
CWE-835- Plataforma
- Python (PyPI)
- Paquete
pypdf, pypdf2- Publicada
- 30.06.2023
- Actualizado
- 11.10.2026 15:17
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-1835 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - PYSEC-2026-3008 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-4vvm-4w3v-6mr8 - CC BY 4.0
Historial de vulnerabilidades: pypdf
Todas las vulnerabilidades publicadas de este paquete (Python (PyPI)), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 51
- Primera → última
- 06.2023 10.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Alta 10
- Media 38
- Baja 3
Divulgaciones por año
- 2023: 2
- 2024: 0
- 2025: 4
- 2026: 45
-
pypdf and PyPDF2 possible Infinite Loop when a comment isn't followed by a character esta entrada
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