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Zlib CVE-2023-45853

CRITICAL
Integer Overflow or Wraparound (CWE-190)
2023-10-14 cve@mitre.org
9.8
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Integer overflow checks
MITRE ATT&CK

1 technique across 1 tactic: Execution

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

Impact

CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

A remote attacker could cause unexpected behavior through arithmetic overflow by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

Act Now Prioritize within 24-48h. Why: Active threat signals + CRITICAL/HIGH severity.
Patch available 2.9% exploitation probability (EPSS)

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AnalysisAI

MiniZip in zlib through 1.3 has an integer overflow and resultant heap-based buffer overflow in zipOpenNewFileInZip4_64 via a long filename, comment, or extra field. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Validate arithmetic operations, use safe integer libraries, check bounds before allocation.

Affected Packages

pypi pyminizip no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package 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 as Integer Overflow (CWE-190), which allows attackers to cause unexpected behavior through arithmetic overflow. MiniZip in zlib through 1.3 has an integer overflow and resultant heap-based buffer overflow in zipOpenNewFileInZip4_64 via a long filename, comment, or extra field. NOTE: MiniZip is not a supported part of the zlib product. NOTE: pyminizip through 0.2.6 is also vulnerable because it bundles an affected zlib version, and exposes the applicable MiniZip code through its compress API. Affected products include: Zlib, Smihica Pyminizip. Version information: through 1.3.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

DescriptionNVD

MiniZip in zlib through 1.3 has an integer overflow and resultant heap-based buffer overflow in zipOpenNewFileInZip4_64 via a long filename, comment, or extra field. NOTE: MiniZip is not a supported part of the zlib product. NOTE: pyminizip through 0.2.6 is also vulnerable because it bundles an affected zlib version, and exposes the applicable MiniZip code through its compress API.

Threat Intelligence Overview

Threat Score
4.0/10
Composite threat intelligence
EPSS Score
2.9%
Top 15% exploitable
Threat Intel
1
1 source
Data Quality
6 sources
Confidence: High
NVD CVE.org EPSS CISA GitHub VulDB

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 CRITICAL
CISA KEV No
Public POC No
EPSS 2.9%
Patch available Yes
Active threat Yes
Deciding rule
Active threat signals + CRITICAL/HIGH severity
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
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

62
Low Medium High Critical
KEV: 0
EPSS: +3
CVSS: +49
PoC: 0
Weaponized: 0
Threat intel: +10
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Integer overflow occurs when an arithmetic operation produces a result that exceeds the maximum value a given integer type can store.

Affected Products (CPE)NVD

cpe:2.3:a:zlib:zlib:*:*:*:*:*:*:*:*
cpe:2.3:a:smihica:pyminizip:*:*:*:*:*:python:*:*

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Threat IntelligenceMISP

CISA Advisories
Sources: CISA (public domain)

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