Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV N H N R U L N L 4.2 .0018 7.8 —
AFFECTED Product Versions Fixed 7-Zip >= 9.18, < 26.01 – —
TIMELINE May 20 Reserved by GitHub_M Jun 5 EXPLOIT PUBLISHED — CVE-2026-48104 (mcmilk 7-Zip). Public exploit reference added. Jun 5 Published (CNA: GitHub_M)
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.
| Date | Event | Detail |
|---|---|---|
| May 20, 2026 | Reserved | Reserved by GitHub_M |
| June 5, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-48104 (mcmilk 7-Zip). Public exploit reference added. |
| June 5, 2026 | Published | Published (CNA: GitHub_M) |
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|---|---|---|---|
| mcmilk | 7-Zip | — | >= 9.18, < 26.01 | — |
Authoritative record: CVE-2026-48104 at cve.org
Vendors: mcmilk
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-48104 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.