Cyber Resilience

CVE-2023-40477

Rarlab Winrar ≤ 6.23

Published
03 May 2024
Modified
04 November 2025
CVSS Score v3 7.8
Click a component to see what it means
Raw vectorCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.12 96th percentile
Risk Priority 83 floored blend · peak EPSS

Summary

CVE-2023-40477 is a high-severity Improper Validation of Array Index (CWE-129) vulnerability in Rarlab Winrar. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

RARLAB WinRAR contains an improper validation of array index vulnerability (CWE-129) in its handling of recovery volumes. The flaw permits an out-of-bounds memory access when processing specially crafted recovery data, enabling remote code execution on affected installations. The issue was originally reported as ZDI-CAN-21233 and carries a CVSS 3.0 score of 7.8.

Remote attackers can trigger the vulnerability by supplying a malicious recovery volume that a user must open or that is reached via a malicious web page. Successful exploitation grants arbitrary code execution in the context of the current WinRAR process; no privileges are required beyond normal user interaction with the file.

Vendor advisories and the Zero Day Initiative disclosure point to updated WinRAR builds that correct the recovery-volume processing logic. The Debian LTS announcement similarly references backported fixes for supported releases. EPSS scores remain elevated near 0.92, indicating sustained exploitation interest following public disclosure.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

RARLAB WinRAR Recovery Volume Improper Validation of Array Index Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of RARLAB WinRAR. User interaction is required to exploit this vulnerability in that the target…

more

must visit a malicious page or open a malicious file. The specific flaw exists within the processing of recovery volumes. The issue results from the lack of proper validation of user-supplied data, which can result in a memory access past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-21233.

CWE(s)
CWE-129

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 →
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-38831Same product: Rarlab Winrar
CVE-2018-20250Same product: Rarlab Winrar
CVE-2025-52331Same product: Rarlab Winrar
CVE-2025-31334Same product: Rarlab Winrar
CVE-2024-30370Same product: Rarlab Winrar
CVE-2023-52594Shared CWE-129
CVE-2024-38562Shared CWE-129
CVE-2024-36015Shared CWE-129
CVE-2025-10158Shared CWE-129
CVE-2023-52728Shared CWE-129

Affected Assets

rarlab
winrar
≤ 6.23

Mitigating Controls

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 input validation and bounds checking that prevent improper array indexing.

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 out-of-bounds array access but does not prevent the weakness by itself.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates input validation and bounds checking that directly prevents improper array indexing.

A.8.26 Application security requirements partial match
prevents

Application security requirements include validation of untrusted input used for indexing or addressing memory structures.

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

Secure architecture principles encourage defensive coding patterns that reduce index-related vulnerabilities.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly require bounds checking and validation of array indices derived from untrusted data.

References