Vulnerability in 7-Zip
CVE-2026-48101
7-Zip is a file archiver with a high compression ratio. Versions 9.21 through 26.00 contain an An uninitialized memory disclosure vulnerability in the UEFI capsule (.scap) parser in 7-Zip. The OpenCapsule function allocates a heap buffer of attacker-declared CapsuleImageSize (up to 1 GiB) without zero-initialization, then reads the file contents into it with ReadStream_FALSE whose return value is silently discarded. If the file is truncated, the unread tail of the buffer retains uninitialized heap memory, which is then exposed as extracted file content via GetStream. Version 26.0.1 fixes the issue.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.003 (20.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 20.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.003 · change: -0.001
Affected products
- 7-Zip
- Mcmilk 7-Zip — versions >= 9.21, < 26.01
Weakness classification (CWE)
References
- https://securitylab.github.com/advisories/GHSL-2026-115_GHSL-2026-122_7-zip/ (Exploit, Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-48101?
- CVE-2026-48101 is a medium-severity vulnerability in 7-Zip, classified under Use of Uninitialized Resource. CVSS score: 6.5/10. Published 2026-06-05.
- How severe is CVE-2026-48101?
- Medium severity. CVSS v3 base score is 6.5 out of 10.