# CVE-2026-48095: 7zip: 7-Zip is a file archiver with a high compression ratio CVE-2026-48095 is fixed in 10 products on 1 platform, first by ALAS2023-2026-1820, released June 8, 2026. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2026-48095 - Priority: High - CVSS: 8.8 (high) - EPSS: 0.0112 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Jun 5, 2026 ## Description 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | 7zip Debian 12.15 (bookworm) | 22.01+really26.01+dfsg-0+deb12u1 | [DEBIAN-CVE-2026-48095](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48095.md) | Jun 24, 2026 | | Linux | 7zip Debian 14 | 26.01+dfsg-1 | [DEBIAN-CVE-2026-48095](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48095.md) | Jun 24, 2026 | | Linux | 7zip amzn 2023 | 26.01-14.amzn2023.0.1 | [ALAS2023-2026-1820](https://patchblox.com/security/data/fix/linux/alas2023-2026-1820.md) | Jun 8, 2026 | | Linux | 7zip opensuse-leap 16.0 | 26.01-160000.1.1 | [OPENSUSE-SU-2026:21038-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21038-1.md) | Jun 23, 2026 | | Linux | 7zip sles 15.6 | 26.01-150400.9.6.1 | [SUSE-SU-2026:2696-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2696-1.md) | Jun 30, 2026 | | Linux | 7zip sles 15.7 | 26.01-150400.9.6.1 | [SUSE-SU-2026:2696-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2696-1.md) | Jun 30, 2026 | | Linux | 7zip sles 16.0 | 26.01-160000.1.1 | [SUSE-SU-2026:22347-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22347-1.md) | Jun 23, 2026 | | Linux | 7zip-debuginfo amzn 2023 | 26.01-14.amzn2023.0.1 | [ALAS2023-2026-1820](https://patchblox.com/security/data/fix/linux/alas2023-2026-1820.md) | Jun 8, 2026 | | Linux | 7zip-debugsource amzn 2023 | 26.01-14.amzn2023.0.1 | [ALAS2023-2026-1820](https://patchblox.com/security/data/fix/linux/alas2023-2026-1820.md) | Jun 8, 2026 | | Linux | 7zip-reduced amzn 2023 | 26.01-14.amzn2023.0.1 | [ALAS2023-2026-1820](https://patchblox.com/security/data/fix/linux/alas2023-2026-1820.md) | Jun 8, 2026 | | Linux | 7zip-reduced-debuginfo amzn 2023 | 26.01-14.amzn2023.0.1 | [ALAS2023-2026-1820](https://patchblox.com/security/data/fix/linux/alas2023-2026-1820.md) | Jun 8, 2026 | | Linux | 7zip-standalone amzn 2023 | 26.01-14.amzn2023.0.1 | [ALAS2023-2026-1820](https://patchblox.com/security/data/fix/linux/alas2023-2026-1820.md) | Jun 8, 2026 | | Linux | 7zip-standalone-all amzn 2023 | 26.01-14.amzn2023.0.1 | [ALAS2023-2026-1820](https://patchblox.com/security/data/fix/linux/alas2023-2026-1820.md) | Jun 8, 2026 | | Linux | 7zip-standalone-all-debuginfo amzn 2023 | 26.01-14.amzn2023.0.1 | [ALAS2023-2026-1820](https://patchblox.com/security/data/fix/linux/alas2023-2026-1820.md) | Jun 8, 2026 | | Linux | 7zip-standalone-debuginfo amzn 2023 | 26.01-14.amzn2023.0.1 | [ALAS2023-2026-1820](https://patchblox.com/security/data/fix/linux/alas2023-2026-1820.md) | Jun 8, 2026 | | Linux | p7zip Debian 12.15 (bookworm) | 16.02+really26.01+dfsg-0+deb12u1 | [DEBIAN-CVE-2026-48095](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48095.md) | Jun 24, 2026 | | Linux | p7zip Debian 13.5 (trixie) | 16.02+transitional.1 | [DEBIAN-CVE-2026-48095](https://patchblox.com/security/data/fix/linux/debian-cve-2026-48095.md) | Jun 24, 2026 | --- Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.