Heap memory disclosure via fragment offset overflow
Published Jun 5, 2026 · Updated Jun 5, 2026
Out-of-bounds read in 7-Zip 9.34 through 26.00 allows attackers to expose heap memory by extracting a crafted SquashFS archive. CHandler::ReadBlock adds an attacker-controlled fragment offset to blockSize in 32-bit arithmetic, allowing wraparound to bypass its bounds check before memcpy reads before the cache buffer. Exploitation requires a 32-bit build and extraction of the malicious archive; leaked heap bytes are written into the extracted file.
Summary
What happened
Out-of-bounds read in 7-Zip 9.34 through 26.00 allows attackers to expose heap memory by extracting a crafted SquashFS archive. CHandler::ReadBlock adds an attacker-controlled fragment offset to blockSize in 32-bit arithmetic, allowing wraparound to bypass its bounds check before memcpy reads before the cache buffer. Exploitation requires a 32-bit build and extraction of the malicious archive; leaked heap bytes are written into the extracted file.
The record
- CVE
- CVE-2026-48092
- Published
- Jun 5, 2026
- Updated
- Jun 5, 2026
- Vendor
- 7-Zip
- Product
- 7-Zip
- Classifications
- CWE-125, CWE-190, T1204.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 5, 2026CVE publishedPublication date reported by the CVE source.
- Jun 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 9.34, < 26.01
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GHSL SquashFS fragment-offset PoC generatorproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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