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 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:
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
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
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | pypdf2 | >= 2.10.5, < 2.10.6 | 2.10.6 |
Referencias
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-hm9v-vj3r-r55m
- https://nvd.nist.gov/vuln/detail/CVE-2023-36807
- https://github.com/py-pdf/pypdf/issues/1329
- https://github.com/py-pdf/pypdf/pull/1331
- https://github.com/py-pdf/pypdf/commit/e6531a25325e7e0174b6a1ba03b57320b5227f6b
- https://github.com/py-pdf/pypdf
- https://pypi.org/project/pypdf2
- https://github.com/advisories/GHSA-hm9v-vj3r-r55m
- 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
pypdf2- Publicada
- 30.06.2023
- Actualizado
- 11.10.2026 13:18
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-1836 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-hm9v-vj3r-r55m - CC BY 4.0
Historial de vulnerabilidades: pypdf2
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
- 4
- Primera → última
- 04.2022 06.2023
- Sin corrección
- 1
- Explotada en ataques
- 0
Distribución por gravedad
- Media 4
Divulgaciones por año
- 2022: 1
- 2023: 3
- 2024: 0
- 2025: 0
- 2026: 0
-
PyPDF2 vulnerable to possible Infinite Loop when reading malformed objects esta entrada
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