Cyber Resilience

CVE-2023-45853

Memory Safety in Zlib ≤ 1.3.1

Memory Safety
Published
14 October 2023
Modified
14 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.032 87th percentile
Risk Priority 76 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-45853 is a critical-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Zlib Zlib. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 13% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

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…

more

also vulnerable because it bundles an affected zlib version, and exposes the applicable MiniZip code through its compress API.

CWE(s)
CWE-190

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-27171Same product: Zlib Zlib
CVE-2026-22184Same product: Zlib Zlib
CVE-2026-27281Shared CWE-190
CVE-2025-58715Shared CWE-190
CVE-2024-43623Shared CWE-190
CVE-2016-1010Shared CWE-190
CVE-2024-30001Shared CWE-190
CVE-2023-38698Shared CWE-190
CVE-2023-24909Shared CWE-190
CVE-2026-2272Shared CWE-190

Affected Assets

zlib
zlib
≤ 1.3.1
smihica
pyminizip
≤ 0.2.6

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.2.6

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require use of safe arithmetic, bounds checks, and testing that prevent integer overflows.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect integer overflows before release.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates input validation and arithmetic checks that prevent integer overflows.

A.8.26 Application security requirements partial match
degrades

Application security requirements include bounds checking and safe arithmetic to avoid overflow conditions.

A.8.27 Secure system architecture and engineering principles partial match
degrades

Secure architecture principles require defensive coding patterns that mitigate integer wraparound risks.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly forbid unsafe integer operations and mandate overflow-safe constructs.

References