# CVE-2020-25221: Privilege escalation in n/a

> A refcount underflow in the Linux kernel allows local attackers to escalate privileges via ptrace or process_vm_readv.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** 10 Sep 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-25221, GHSA-442r-3r9f-48cm, UBUNTU-CVE-2020-25221

## What is CVE-2020-25221?

CVE-2020-25221 is a high-severity vulnerability in Linux kernel, published on 10 Sep 2020. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

get_gate_page in mm/gup.c in the Linux kernel 5.7.x and 5.8.x before 5.8.7 allows privilege escalation because of incorrect reference counting (caused by gate page mishandling) of the struct page that backs the vsyscall page. The result is a refcount underflow. This can be triggered by any 64-bit process that can use ptrace() or process_vm_readv(), aka CID-9fa2dd946743.

Weakness: CWE-672 (Operation on a Resource after Expiration or Release)

## Which versions are affected by CVE-2020-25221?

It affects 6 products.


Products: Linux kernel, Netapp Cloud Backup, Netapp Hci Compute Node, Netapp Solidfire\, Enterprise Sds \& Hci Storage Node, Netapp Solidfire \& Hci Management Node, Netapp Solidfire Baseboard Management Controller.

## How do I fix CVE-2020-25221?

Apply the vendor's patch.

## Is CVE-2020-25221 being exploited?

There is no known exploitation of CVE-2020-25221 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-25221 and fix it if it is affected.

What it is: CVE-2020-25221 is a high-severity vulnerability in Linux kernel, published on 10 Sep 2020. 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-2020-25221 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2020-25221/ (Markdown: https://insights.sbomify.com/CVE-2020-25221/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-25221
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-25221
- OSV: https://osv.dev/vulnerability/CVE-2020-25221

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-25221/
Summaries are generated and may contain mistakes; the official description above is the record.