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Change History

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.

AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

CWE-125

https://securitylab.github.com/advisories/GHSL-2026-115_GHSL-2026-122_7-zip/