CVE-2026-48092: 7-Zip SquashFS Fragment Offset Overflow (GHSL-2026-116)

Severity: high (CVSS 8.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-05 · updated 2026-06-17
Weakness: CWE-125

Description

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.

Affected products

7-Zip: from 9.34 before 26.01 — fixed in 26.01

How to fix

Upgrade to a fixed version: 7-Zip 26.01. Check the vendor advisory for mitigations.

References

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