CVE-2026-48101: 7-Zip is a file archiver with a high compression ratio
CVE-2026-48101 analysis covering impact, affected products, versions, remediation, and cross-checked defender guidance.
CVE-2026-48101 is a vulnerability published by NVD on 05/06/2026.
What happened
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.
Affected products and versions
- NVD has not published a normalized affected-product configuration yet.
Severity and weakness
CVSS: MEDIUM 6.5. Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.
Weaknesses: CWE-908.
Known exploitation
No CISA KEV entry is currently attached to the NVD record.
What defenders should do
- Identify whether the affected product and version range exists in production.
- Review vendor advisories and release notes before change windows.
- Patch, upgrade, disable the vulnerable component, or apply vendor mitigations.
- Verify the running version after deployment, not only the package inventory.
Official and supporting references
- No vendor advisory tagged by NVD at draft time.