Vulnerabilities

7-Zip XZ Decompression Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of 7-Zip. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the processing of XZ chunked data. Crafted XZ-compressed data can trigger an overflow of a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-30169.

7-Zip for Windows through 26.01 fails to preserve the Mark-of-the-Web when extracting a crafted RAR5 archive, because its guard that suppresses an archive-supplied Zone.Identifier stream matches the exact name 'Zone.Identifier' while a RAR5 STM record named ':Zone.Identifier:$DATA' is not matched and NTFS canonicalizes it to the same stream, overwriting the propagated Internet-zone marker with ZoneId=0. A second STM record named '::$DATA' overwrites the extracted file's default data stream, letting an attacker defeat SmartScreen/MotW warnings and spoof file content.

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 = 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.

7-Zip ZIP File Parsing Directory Traversal Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of 7-Zip. Interaction with this product is required to exploit this vulnerability but attack vectors may vary depending on the implementation. The specific flaw exists within the handling of symbolic links in ZIP files. Crafted data in a ZIP file can cause the process to traverse to unintended directories. An attacker can leverage this vulnerability to execute code in the context of a service account. Was ZDI-CAN-26743.

CVE-2025-11001 is a directory traversal vulnerability (CWE-22) in 7-Zip's handling of symbolic links inside ZIP archives, which an attacker can leverage for arbitrary code execution. Exploitation requires interaction with the product — typically a user opening or extracting a crafted ZIP (the CVSS vector is local with user interaction required), though real-world attack vectors vary by implementation — allowing the attacker to escape the intended extraction directory and run code with the privileges of the account doing the extraction, often a service account. Any 7-Zip installation that processes untrusted archives, from desktop users to server-side automation and pipelines, is potentially affected; the disclosure data does not specify a vulnerable version range. Security outlets report a public proof-of-concept and active exploitation in the wild, and the UK NHS has issued an advisory; the flaw carries a high EPSS score (27% probability of exploitation within 30 days, 98th percentile) but is not yet in CISA's KEV catalog.

Do: Update 7-Zip to the latest patched release available from the vendor (the exact fixed version number is not specified in this data). Until patched, avoid opening or auto-extracting ZIP archives from untrusted sources — especially archives containing symbolic links — and audit any server-side jobs, CI pipelines, or gateway services that invoke 7-Zip on external archives, since code executes with the service account's privileges; related coverage also flags code execution via crafted XZ archives, so treat those cautiously as well. Given reports of in-the-wild exploitation and the NHS advisory, prioritize patching shared and high-interaction systems.

7-Zip before 25.01 does not always properly handle symbolic links during extraction.

7-Zip is a file archiver with a high compression ratio. Zeroes written outside heap buffer in RAR5 handler may lead to memory corruption and denial of service in versions of 7-Zip prior to 25.0.0. Version 25.0.0 contains a fix for the issue.

7-Zip 22.01 does not report an error for certain invalid xz files, involving block flags and reserved bits. Some later versions are unaffected.

CVE-2025-0411 is a protection-mechanism bypass in 7-Zip's handling of archived files: when extracting a crafted archive that carries the Mark-of-the-Web, 7-Zip fails to propagate the MotW flag to the extracted files. Exploitation requires user interaction, as the target must visit a malicious page or open a malicious archive. Because the extracted files lose their MotW designation, Windows skips its usual security prompts on attacker-supplied executables or scripts, allowing arbitrary code execution in the context of the current user. Anyone running affected 7-Zip installations is exposed, including NetApp Active IQ Unified Manager deployments that incorporate 7-Zip. The flaw was exploited as a zero-day — Russian cybercrime groups and SmokeLoader campaigns, notably targeting Ukrainian organizations, abused it — and CISA added it to the Known Exploited Vulnerabilities catalog on 2025-02-06.

Do: Upgrade 7-Zip to the latest patched release per vendor guidance, and for NetApp Active IQ Unified Manager apply the update specified in NetApp's security advisory; the CISA KEV required action is to apply vendor mitigations or discontinue use. Until patched, treat archives from untrusted sources with caution and verify extracted executables manually, since MotW prompts will not fire on extracted files. Hunt for signs of SmokeLoader-style post-extraction execution in user workstations.

7-Zip contains a remote code execution flaw in its Zstandard (zstd) decompression implementation, where insufficient validation of user-supplied data allows an integer underflow before writing to memory. Exploitation requires interaction with the library — typically an application or user processing a crafted Zstandard-compressed stream or archive — and the attack vector can vary depending on how 7-Zip is integrated. A successful attacker executes arbitrary code in the context of the current process, gaining the privileges of whatever application invoked the decompressor. Anyone running an affected 7-Zip installation whose workflows decompress Zstandard data is exposed, with the highest risk on endpoints where users open untrusted archives. As of publication there is no entry in CISA's KEV and no known public proof-of-concept, but a high EPSS score (22.6% probability of exploitation within 30 days, 98th percentile) indicates an elevated near-term exploitation risk.

Do: Upgrade 7-Zip to the latest release available from 7-zip.org and audit third-party applications that bundle or embed 7-Zip components (e.g., 7z.dll) to process archives, updating those as vendors patch. Until patched, avoid opening Zstandard-compressed archives or streams from untrusted sources, since the CVSS vector indicates user interaction is required and the attack surface varies with how the library is integrated.

7-Zip SquashFS File Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of 7-Zip. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of SQFS files. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-18589.

Ppmd7.c in 7-Zip before 23.00 allows an integer underflow and invalid read operation via a crafted 7Z archive.

p7zip 16.02 was discovered to contain a heap-buffer-overflow vulnerability via the function NArchive::NZip::CInArchive::FindCd(bool) at CPP/7zip/Archive/Zip/ZipIn.cpp. NOTE: the Supplier has found that this is not a buffer overflow; at most an out-of-bounds read can occur.

7-Zip through 21.07 on Windows allows privilege escalation and command execution when a file with the .7z extension is dragged to the Help>Contents area. This is caused by misconfiguration of 7z.dll and a heap overflow. The command runs in a child process under the 7zFM.exe process. NOTE: multiple third parties have reported that no privilege escalation can occur

Incorrect initialization logic of RAR decoder objects in 7-Zip 18.03 and before can lead to usage of uninitialized memory, allowing remote attackers to cause a denial of service (segmentation fault) or execute arbitrary code via a crafted RAR archive.

7-Zip through 18.01 on Windows implements the "Large memory pages" option by calling the LsaAddAccountRights function to add the SeLockMemoryPrivilege privilege to the user's account, which makes it easier for attackers to bypass intended access restrictions by using this privilege in the context of a sandboxed process. Note: This has been disputed by 3rd parties who argue this is a valid feature of Windows.

Insufficient exception handling in the method NCompress::NRar3::CDecoder::Code of 7-Zip before 18.00 and p7zip can lead to multiple memory corruptions within the PPMd code, allows remote attackers to cause a denial of service (segmentation fault) or execute arbitrary code via a crafted RAR archive.

Heap-based buffer overflow in the NCompress::NShrink::CDecoder::CodeReal method in 7-Zip before 18.00 and p7zip allows remote attackers to cause a denial of service (out-of-bounds write) or potentially execute arbitrary code via a crafted ZIP archive.

Untrusted search path vulnerability in 7 Zip for Windows 16.02 and earlier allows remote attackers to gain privileges via a Trojan horse DLL in an unspecified directory.

Heap-based buffer overflow in the NArchive::NHfs::CHandler::ExtractZlibFile method in 7zip before 16.00 and p7zip allows remote attackers to execute arbitrary code via a crafted HFS+ image.

A null pointer dereference bug affects the 16.02 and many old versions of p7zip. A lack of null pointer check for the variable folders.PackPositions in function CInArchive::ReadAndDecodePackedStreams in CPP/7zip/Archive/7z/7zIn.cpp, as used in the 7z.so library and in 7z applications, will cause a crash and a denial of service when decoding malformed 7z files.

The CInArchive::ReadFileItem method in Archive/Udf/UdfIn.cpp in 7zip 9.20 and 15.05 beta and p7zip allows remote attackers to cause a denial of service (out-of-bounds read) or execute arbitrary code via the PartitionRef field in the Long Allocation Descriptor in a UDF file.