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PyPDF2 quadratic runtime with malformed PDF missing xref marker

Moderate severity GitHub Reviewed Published Jun 30, 2023 in py-pdf/pypdf • Updated Nov 6, 2023

Package

pip PyPDF2 (pip)

Affected versions

<= 1.27.8

Patched versions

1.27.9

Description

Impact

An attacker who uses this vulnerability can craft a PDF which leads to unexpected long runtime.
This quadratic runtime blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage.

Patches

py-pdf/pypdf#808

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

References

References

@MartinThoma MartinThoma published to py-pdf/pypdf Jun 30, 2023
Published by the National Vulnerability Database Jun 30, 2023
Published to the GitHub Advisory Database Jun 30, 2023
Reviewed Jun 30, 2023
Last updated Nov 6, 2023

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(33rd percentile)

Weaknesses

Inefficient Algorithmic Complexity

An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. Learn more on MITRE.

CVE ID

CVE-2023-36810

GHSA ID

GHSA-jrm6-h9cq-8gqw

Source code

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