Uncontrolled Memory Allocation in sharpcompress - #VU166169
Published: November 13, 2026
Vulnerability identifier: #VU166169
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-789
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service through memory exhaustion.
The vulnerability exists due to excessive memory allocation in SharpCompress's RAR5 UnpackV2017.Init when processing an attacker-controlled dictionary/window size without an effective bound before decoding entry data. A remote attacker can induce a victim to extract or read an entry from a crafted 72-byte RAR5 archive with zero compressed bytes to trigger a 1 GiB window allocation and exhaust process memory.
Affected software
sharpcompress
Remediation
Install security update from vendor's website.
sharpcompress - update to 0.50.9