Cyber Resilience

CVE-2023-40477

High

Published: 03 May 2024

Published
03 May 2024
Modified
04 November 2025
KEV Added
Patch
CVSS Score v3 7.8 CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.9189 99.7th percentile
Risk Priority 71 60% EPSS · 20% KEV · 20% CVSS

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, ranked in the top 0.3% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis

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.

EU & UK References

Vulnerability details

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…

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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)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

rarlab
winrar
≤ 6.23

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References