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Security Advisories: GSA_kwCzR0hTQS00dnZtLTR3M3YtNm1yOM4AA0KJ

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""):
Permalink: https://github.com/advisories/GHSA-4vvm-4w3v-6mr8
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS00dnZtLTR3M3YtNm1yOM4AA0KJ
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: 10 months ago
Updated: 6 months ago


CVSS Score: 6.2
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Identifiers: GHSA-4vvm-4w3v-6mr8, CVE-2023-36464
References: Repository: https://github.com/py-pdf/pypdf
Blast Radius: 22.2

Affected Packages

pypi:PyPDF2
Dependent packages: 126
Dependent repositories: 1,626
Downloads: 6,383,106 last month
Affected Version Ranges: >= 2.2.0, <= 3.0.1
No known fixed version
All affected versions: 2.2.0, 2.2.1, 2.3.0, 2.3.1, 2.4.0, 2.4.1, 2.4.2, 2.5.0, 2.6.0, 2.7.0, 2.8.0, 2.8.1, 2.9.0, 2.10.0, 2.10.1, 2.10.2, 2.10.3, 2.10.4, 2.10.5, 2.10.6, 2.10.7, 2.10.8, 2.10.9, 2.11.0, 2.11.1, 2.11.2, 2.12.0, 2.12.1, 3.0.0, 3.0.1
pypi:pypdf
Dependent packages: 167
Dependent repositories: 3,809
Downloads: 4,817,141 last month
Affected Version Ranges: >= 3.1.0, < 3.9.0
Fixed in: 3.9.0
All affected versions: 3.1.0, 3.2.0, 3.2.1, 3.3.0, 3.4.0, 3.4.1, 3.5.0, 3.5.1, 3.5.2, 3.6.0, 3.7.0, 3.7.1, 3.8.0, 3.8.1
All unaffected versions: 3.9.0, 3.9.1, 3.10.0, 3.11.0, 3.11.1, 3.12.0, 3.12.1, 3.12.2, 3.13.0, 3.14.0, 3.15.0, 3.15.1, 3.15.2, 3.15.3, 3.15.4, 3.15.5, 3.16.0, 3.16.1, 3.16.2, 3.16.3, 3.16.4, 3.17.0, 3.17.1, 3.17.2, 3.17.3, 3.17.4, 4.0.0, 4.0.1, 4.0.2, 4.1.0, 4.2.0