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Pypdf CVE-2023-36464

MEDIUM
Loop with Unreachable Exit Condition (Infinite Loop) (CWE-835)
2023-06-27 security-advisories@github.com
5.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Loop termination conditions
MITRE ATT&CK

1 technique across 1 tactic: Impact

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 5.5 (MEDIUM). Attack characteristics: local attack vector, low complexity, no privileges required, user interaction required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.4% exploitation probability (EPSS)

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AnalysisAI

pypdf is an open source, pure-python PDF library. Rated medium severity (CVSS 5.5), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affected Packages

pypi pypdf fix: 3.9.0
pypi pypdf2 fix: 3.9.0

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 2 packages in pypi

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-835. pypdf is an open source, pure-python PDF library. In affected versions an attacker may craft a PDF which leads to an infinite loop if __parse_content_stream is executed. That is, for example, the case if the user extracted text from such a PDF. This issue was introduced in pull request #969 and resolved in pull request #1828. Users are advised to upgrade. Users unable to upgrade may modify the line while peek not in (b"\r", b"\n") in pypdf/generic/_data_structures.py to while peek not in (b"\r", b"\n", b""). Affected products include: Pypdf Project Pypdf, Pypdf2 Project Pypdf2.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.5 MEDIUM
AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionNVD

pypdf is an open source, pure-python PDF library. In affected versions an attacker may craft a PDF which leads to an infinite loop if __parse_content_stream is executed. That is, for example, the case if the user extracted text from such a PDF. This issue was introduced in pull request #969 and resolved in pull request #1828. Users are advised to upgrade. Users unable to upgrade may modify the line while peek not in (b"\r", b"\n") in pypdf/generic/_data_structures.py to while peek not in (b"\r", b"\n", b"").

Threat Intelligence Overview

EPSS Score
0.4%
Top 73% exploitable
Exploit
POC
Public exploit code exists
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC Yes
EPSS 0.4%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Small
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

48
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +28
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)NVD

cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:*
cpe:2.3:a:pypdf2_project:pypdf2:*:*:*:*:*:*:*:*

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