{"id":"UBUNTU-CVE-2026-48095","details":"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 \u003c\u003c (BlockSizeLog + CompressionUnit), and a crafted image with ClusterSizeLog \u003e= 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.","modified":"2026-06-12T09:04:20.247903123Z","published":"2026-06-05T15:16:00Z","upstream":["CVE-2026-48095"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-48095"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-48095"},{"type":"REPORT","url":"https://securitylab.github.com/advisories/GHSL-2026-140_7-Zip/"}],"affected":[{"package":{"name":"p7zip","ecosystem":"Ubuntu:14.04:LTS","purl":"pkg:deb/ubuntu/p7zip?arch=source&distro=trusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.20.1~dfsg.1-4","9.20.1~dfsg.1-4+deb7u1build0.14.04.1","9.20.1~dfsg.1-4+deb7u2build0.14.04.1","9.20.1~dfsg.1-4+deb7u3build0.14.04.1"],"ecosystem_specific":{"binaries":[{"binary_name":"p7zip","binary_version":"9.20.1~dfsg.1-4+deb7u3build0.14.04.1"},{"binary_name":"p7zip-full","binary_version":"9.20.1~dfsg.1-4+deb7u3build0.14.04.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48095.json"}},{"package":{"name":"p7zip","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/p7zip?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.20.1~dfsg.1-4.2","9.20.1~dfsg.1-4.2ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_version":"9.20.1~dfsg.1-4.2ubuntu0.1","binary_name":"p7zip"},{"binary_version":"9.20.1~dfsg.1-4.2ubuntu0.1","binary_name":"p7zip-full"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48095.json"}},{"package":{"name":"p7zip","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/p7zip?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["16.02+dfsg-4","16.02+dfsg-5","16.02+dfsg-6"],"ecosystem_specific":{"binaries":[{"binary_name":"p7zip","binary_version":"16.02+dfsg-6"},{"binary_version":"16.02+dfsg-6","binary_name":"p7zip-full"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48095.json"}},{"package":{"name":"p7zip","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/p7zip?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["16.02+dfsg-7","16.02+dfsg-7build1"],"ecosystem_specific":{"binaries":[{"binary_name":"p7zip","binary_version":"16.02+dfsg-7build1"},{"binary_name":"p7zip-full","binary_version":"16.02+dfsg-7build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48095.json"}},{"package":{"name":"p7zip","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/p7zip?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["16.02+dfsg-8"],"ecosystem_specific":{"binaries":[{"binary_version":"16.02+dfsg-8","binary_name":"p7zip"},{"binary_name":"p7zip-full","binary_version":"16.02+dfsg-8"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48095.json"}},{"package":{"name":"7zip","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/7zip?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["21.03~beta+dfsg-6","21.04~beta+dfsg-1","21.06+dfsg-1","21.07+dfsg-1","21.07+dfsg-2","21.07+dfsg-3","21.07+dfsg-4","21.07+dfsg-4ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"7zip","binary_version":"21.07+dfsg-4ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48095.json"}},{"package":{"name":"7zip","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/7zip?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["23.01+dfsg-3","23.01+dfsg-7","23.01+dfsg-8","23.01+dfsg-11","23.01+dfsg-11ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"7zip","binary_version":"23.01+dfsg-11ubuntu0.1~esm1"},{"binary_name":"7zip-standalone","binary_version":"23.01+dfsg-11ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48095.json"}},{"package":{"name":"7zip","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/7zip?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["24.09+dfsg-7","24.09+dfsg-8","25.00+dfsg-1","25.01+dfsg-1","25.01+dfsg-2"],"ecosystem_specific":{"binaries":[{"binary_name":"7zip","binary_version":"25.01+dfsg-2"},{"binary_name":"7zip-standalone","binary_version":"25.01+dfsg-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48095.json"}},{"package":{"name":"7zip","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/7zip?arch=source&d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