Security 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 0.11 96th percentile
Risk Priority 83 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-2023-40477 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 Steganography (T1001.002); 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

T1001.002 Steganography Command And Control
Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.
attack.mitre.org →
T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
attack.mitre.org →
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
attack.mitre.org →
T1008 Fallback Channels Command And Control
Adversaries may use fallback or alternate communication channels if the primary channel is compromised or inaccessible in order to maintain reliable command and control and to avoid data transfer thresholds.
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-2024-30370Same product: Rarlab Winrar
CVE-2025-31334Same product: Rarlab Winrar
CVE-2025-37752Shared CWE-129
CVE-2024-38562Shared CWE-129
CVE-2024-24563Shared CWE-129
CVE-2024-53203Shared CWE-129
CVE-2024-45550Shared 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 partial match
blocks

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.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References