# CVE-2025-8860: Qemu-kvm: uefi-vars: information disclosure vulnerability in uefi_vars_write callback

> A guest VM can read uninitialized heap memory from the QEMU UEFI vars device, potentially exposing sensitive host process data.

- **Severity:** Low 3.3 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Feb 2026
- **Updated:** 19 Feb 2026
- **Also known as:** DEBIAN-CVE-2025-8860, GHSA-xrj7-v4x4-74hr

## What is CVE-2025-8860?

CVE-2025-8860 is a low-severity vulnerability in Red Hat Enterprise Linux 10, published on 18 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw was found in QEMU in the uefi-vars virtual device. When the guest writes to register UEFI_VARS_REG_BUFFER_SIZE, the .write callback `uefi_vars_write` is invoked. The function allocates a heap buffer without zeroing the memory, leaving the buffer filled with residual data from prior allocations. When the guest later reads from register UEFI_VARS_REG_PIO_BUFFER_TRANSFER, the .read callback `uefi_vars_read` returns leftover metadata or other sensitive process memory from the previously allocated buffer, leading to an information disclosure vulnerability.

Weakness: CWE-212 (Improper Removal of Sensitive Information Before Storage or Transfer)

## Which versions are affected by CVE-2025-8860?


## How do I fix CVE-2025-8860?

Apply the vendor's patch.

## Is CVE-2025-8860 being exploited?

There is no known exploitation of CVE-2025-8860 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-8860 and fix it if it is affected.

What it is: CVE-2025-8860 is a low-severity vulnerability in Red Hat Enterprise Linux 10, published on 18 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-8860 in the wild and no public exploit code.

Affected product: Red Hat Enterprise Linux 10. 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-2025-8860/ (Markdown: https://insights.sbomify.com/CVE-2025-8860/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-8860
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-8860
- OSV: https://osv.dev/vulnerability/CVE-2025-8860

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-8860/
Summaries are generated and may contain mistakes; the official description above is the record.