CVE-2026-48104
Published: June 5th, 2026
7-Zip is a file archiver with a high compression ratio. Versions 9.18 through 26.00 contain an uninitialized heap read in the SquashFS archive handler caused by a sparsely populated index array. In the SquashFS handler, _blockToNode is allocated with capacity for every metadata block but populated only when an inode crosses a block boundary, so a crafted image with few inodes spanning many blocks leaves most slots holding raw heap contents (the underlying allocator does not zero-initialize POD storage). When OpenDir looks up an attacker-influenced blockIndex (derived from the RootInode superblock field), it reads two of these uninitialized slots and passes them as the left/right bounds of a binary search over _nodesPos, which dereferences the midpoint without bounds checking; if the resulting value happens to match the search key, the returned index is used to read a full node struct from _nodes whose fields feed further directory parsing, forming a chained OOB read primitive that is heap-layout-dependent and not reliably triggerable. The SquashFS handler is enabled by default in stock 7z.dll and the issue triggers during Open() with no interaction beyond opening the file; impact is denial of service from wild-pointer dereference and potential heap information disclosure, with no write primitive. Version 26.01 fixes the issue.
MEDIUM
CVSS v3: 4.2
CVSS v3: 4.2
Status
| DocFilters Release | Package | State | Justification | Comment |
|---|---|---|---|---|
| 26.3 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 26.2 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 26.1 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 25.4 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 25.3 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 25.2 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 25.1 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 24.4 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 24.4.0 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 24.3 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 24.2 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 24.1 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 23.3 | 7-zip (23.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 23.2 | 7-zip (17.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 23.1 | 7-zip (17.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
| 22.4 | 7-zip (17.01) | Not Affected | Code Not Present | The vulnerability exists in the SquashFS handler (OpenDir / _blockToNode / _nodesPos in SquashfsHandler.cpp), which is part of the full 7-Zip application and is not present in the LZMA SDK. Document Filters consumes LZMA SDK 23.01, whose Archive directory ships only the 7z, LZMA, XZ, and Split handlers; SquashfsHandler.cpp does not exist in the SDK distribution and is not included in the Document Filters build source list (external/CMakeLists.txt, which compiles only the 7z, LZMA, and XZ handlers). The vulnerable OpenDir function and the _blockToNode/_nodesPos structures are therefore never compiled or reachable. |
Severity score breakdown
Attack Complexity
HIGH
Attack Vector
NETWORK
Availability Impact
LOW
Base Score
4.2
Base Severity
MEDIUM
Confidentiality Impact
LOW
Integrity Impact
NONE
Privileges Required
NONE
Scope
UNCHANGED
User Interaction
REQUIRED
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:L
Version
3.1