title: Manipulated inline images can cause Infinite Loop in PyPDF2
description: PyPDF2 is an open source python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. In versions prior to 1.27.5 an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop if the PyPDF2 if the code attempts to get the content stream. The reason is that the last while-loop in `ContentStream._readInlineImage` only terminates when it finds the `EI` token, but never actually checks if the stream has already ended. This issue has been resolved in version `1.27.5`. Users unable to upgrade should validate and PDFs prior to iterating over their content stream.
problem types: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
affected:
{
vendor: py-pdf
product: PyPDF2
versions:
version: < 1.27.5, status: affected
}
metrics:
cvssV3_1: [
version: 3.1
vectorString: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
attackVector: LOCAL
attackComplexity: LOW
privilegesRequired: NONE
userInteraction: NONE
scope: UNCHANGED
confidentialityImpact: NONE
integrityImpact: NONE
availabilityImpact: HIGH
baseScore: 6.2
baseSeverity: MEDIUM
]