# CVE-2026-48101: GHSL-2026-117: 7-Zip UEFI Capsule uninitialized heap memory disclosure

> An attacker can disclose uninitialized heap memory by crafting a truncated UEFI capsule file, potentially exposing sensitive data from the victim's system.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`)
- **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:** Yes
- **Published:** 5 Jun 2026
- **Updated:** 5 Jun 2026
- **Also known as:** ALPINE-CVE-2026-48101, DEBIAN-CVE-2026-48101, ECHO-7b47-8f62-c1ef, MINI-p9wf-x8pp-whqr, UBUNTU-CVE-2026-48101

## What is CVE-2026-48101?

CVE-2026-48101 is a medium-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 9.21 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.

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2026-48101?

It affects 1 product.


Products: 7-Zip 7-Zip.

## How do I fix CVE-2026-48101?

Upgrade to a fixed version.

## Is CVE-2026-48101 being exploited?

There is no known exploitation of CVE-2026-48101 in the wild and no public exploit code.

## Other vulnerabilities in mcmilk 7-Zip

- [CVE-2025-0411](https://insights.sbomify.com/CVE-2025-0411/): 7-Zip Mark of the Web Bypass (high 7.0, exploited in the wild)
- [CVE-2008-6536](https://insights.sbomify.com/CVE-2008-6536/): Other in n/a (critical 10.0)
- [CVE-2026-48095](https://insights.sbomify.com/CVE-2026-48095/): GHSL-2026-140_7-Zip: 7-Zip has a heap buffer overflow via NTFS compressed stream buffer under-allocation (high 8.8)
- [CVE-2018-10172](https://insights.sbomify.com/CVE-2018-10172/): Privilege escalation in n/a (high 8.8)
- [CVE-2016-2335](https://insights.sbomify.com/CVE-2016-2335/): Memory corruption in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48101 and fix it if it is affected.

What it is: CVE-2026-48101 is a medium-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.
Exploitation: There is no known exploitation of CVE-2026-48101 in the wild and no public exploit code.

Affected product: mcmilk 7-Zip. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-48101/ (Markdown: https://insights.sbomify.com/CVE-2026-48101/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48101
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48101
- OSV: https://osv.dev/vulnerability/CVE-2026-48101

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-48101/
Summaries are generated and may contain mistakes; the official description above is the record.