CVE detail
CVE-2026-48095
7-Zip is a file archiver with a high compression ratio. Versions 26.00 and prior contain a heap buffer overflow vulnerability caused by an under-allocation in the NTFS compressed stream buffer (GetCuSize shift UB), potentially allowing attackers to cause arbitrary code execution or application crashes. CInStream::GetCuSize() in the NTFS handler computes the compression-unit buffer size as (UInt32)1 << (BlockSizeLog + CompressionUnit), and a crafted image with ClusterSizeLog >= 28 and CompressionUnit == 4 drives the exponent to 32, which is undefined behavior and collapses on x86/x64 so _inBuf is allocated as 1 byte. ReadStream_FALSE then writes up to 256 MB of attacker-controlled data into that 1-byte buffer in 64 KB iterations, and because the CInStream object sits only 304 bytes after _inBuf, its vtable pointer is overwritten and the next dispatched call achieves a vtable hijack. On 32-bit builds the overflow is unconditionally reached; on 64-bit it requires the parallel 8 GB _outBuf allocation to succeed, otherwise failing closed to denial of service. The NTFS handler is enabled by default in stock 7z.dll and, via signature-based fallback matching "NTFS " at offset 3, will open a crafted image regardless of file extension during extraction or testing. Version 26.01 fixes the issue.
Buzz score
Why this CVE is surfacing
This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.
Buzz score components · mention 11.0 · diversity 10.0 · KEV 0.0 · OTX 0.0 · PoC 0.0
Why it matters now
Mention timeline
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Evidence
Source links by recency
2 source links · newest first
No excerpt available.
Patchsourceforge.netJun 5, 2026, 3:16 PM- https://securitylab.github.com/advisories/GHSL-2026-140_7-Zip/securitylab.github.com
No excerpt available.
Exploitsecuritylab.github.comJun 5, 2026, 3:16 PM
Exploit code
Public exploit repository references
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