7-Zip is a file archiver with a high compression ratio. Versions 9.34 through 26.00 contain a heap memory disclosure via SquashFS fragment offset integer overflow on 32-bit builds. 32-bit integer overflow in the SquashFS ReadBlock function allows an attacker-controlled node.Offset value to bypass the fragment bounds check, causing memcpy to read heap memory preceding the cache buffer into the extracted file. The vulnerability is exploitable only on 32-bit builds of 7-Zip where size_t is 32 bits, allowing the addition offsetInBlock + blockSize to wrap modulo 2³². On 64-bit builds the addition is promoted to 64 bits and the check correctly rejects the input. Version 26.01 patches the issue.

7zip-26.02-2.1 on GA media

Security update for 7zip

Affected: Ubuntu:14.04:LTS: p7zip, Ubuntu:16.04:LTS: p7zip, Ubuntu:18.04:LTS: p7zip, Ubuntu:20.04:LTS: p7zip, Ubuntu:22.04:LTS: p7zip, Ubuntu:Pro:22.04:LTS: 7zip, Ubuntu:Pro:24.04:LTS: 7zip, Ubuntu:25.10: 7zip, Ubuntu:26.04:LTS: 7zip

7-Zip is a file archiver with a high compression ratio. Versions 9.34 through 26.00 contain a heap memory disclosure via SquashFS fragment offset integer overflow on 32-bit builds. 32-bit integer overflow in the SquashFS ReadBlock function allows an attacker-controlled node.Offset value to bypass the fragment bounds check, causing memcpy to read heap memory preceding the cache buffer into the extracted file. The vulnerability is exploitable only on 32-bit builds of 7-Zip where size_t is 32 bits, allowing the addition offsetInBlock + blockSize to wrap modulo 2³². On 64-bit builds the addition is promoted to 64 bits and the check correctly rejects the input. Version 26.01 patches the issue.

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in 7-Zip ausnutzen, um Speicherinhalte offenzulegen, einen Denial-of-Service auszulösen oder beliebigen Code auszuführen.