CVE-2026-48102 GHSL-2026-118: 7-Zip UDF Field OOB Read
A heap out-of-bounds read in 7-Zip's UDF handler allows attackers to disclose limited memory data or cause crashes via crafted ISO/UDF images.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-48102?
CVE-2026-48102 is a low-severity vulnerability in mcmilk 7-Zip, published on 5 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
7-Zip is a file archiver with a high compression ratio. Versions 9.11 through 26.00 contain a heap out-of-bounds read of up to 3 bytes in the UDF disc image handler's File Identifier Descriptor parser. In CFileId::Parse (CPP/7zip/Archive/Udf/UdfIn.cpp), after validating size < 38 + idLen + impLen and advancing processed to 38 + impLen + idLen, the alignment-padding loop reads p[processed] while incrementing up to 3 times to reach a 4-byte boundary, and the processed <= size bounds check only runs after the loop. When (38 + impLen + idLen) % 4 != 0 and 38 + impLen + idLen == size, the loop reads 1 to 3 bytes past the end of the exact-size heap buffer allocated via buf.Alloc((size_t)item.Size). The UDF handler is registered for .iso and .udf files and auto-detected by signature, and the OOB read triggers during Open() when listing or extracting a crafted UDF image. Impact is limited to information disclosure (a 1-bit oracle per OOB byte via open/fail behavior) and denial of service (crash under hardened allocators); there is no write primitive. Version 26.01 fixes the issue.
Weakness: CWE-125
Which versions are affected by CVE-2026-48102?
It affects 1 product.
Products include 7-Zip 7-Zip.
How do I fix CVE-2026-48102?
Upgrade to a fixed version.
Is CVE-2026-48102 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-48102 exists.
Other vulnerabilities in mcmilk 7-Zip
Sources
Also known as ALPINE-CVE-2026-48102, DEBIAN-CVE-2026-48102, ECHO-ebb4-90fc-823e, MINI-2vgp-32mj-p6x8, UBUNTU-CVE-2026-48102.