# CVE-2020-21913: Use after free in n/a

> A use-after-free vulnerability in the ICU library's pkgdata tool allows attackers to potentially execute arbitrary code or cause a denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 20 Sep 2021
- **Updated:** 14 Oct 2026
- **Also known as:** ALPINE-CVE-2020-21913, CLEANSTART-2026-AK78825, DEBIAN-CVE-2020-21913, DLA-2784-1, DSA-5014-1, GHSA-3vq4-8jw3-cwr6, OESA-2021-1406, SUSE-SU-2022:3140-1, SUSE-SU-2022:3141-1, SUSE-SU-2022:3142-1, UBUNTU-CVE-2020-21913, USN-5133-1

## What is CVE-2020-21913?

CVE-2020-21913 is a medium-severity use after free vulnerability in Debian Debian Linux, published on 20 Sep 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

International Components for Unicode (ICU-20850) v66.1 was discovered to contain a use after free bug in the pkg_createWithAssemblyCode function in the file tools/pkgdata/pkgdata.cpp.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2020-21913?

It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `icu` | SUSE:Linux Enterprise Micro 5.1 | All versions | 65.1-150200.4.5.1 |
| `icu` | SUSE:Linux Enterprise Micro 5.2 | All versions | 65.1-150200.4.5.1 |
| `icu` | SUSE:Linux Enterprise Module for Basesystem 15 SP3 | All versions | 65.1-150200.4.5.1 |
| `icu` | SUSE:Linux Enterprise Module for Basesystem 15 SP4 | All versions | 65.1-150200.4.5.1 |
| `icu` | SUSE:Linux Enterprise Module for Legacy 15 SP3 | All versions | 60.2-150000.3.12.1 |
| `icu` | SUSE:Linux Enterprise Module for Legacy 15 SP4 | All versions | 60.2-150000.3.12.1 |
| `icu` | SUSE:Linux Enterprise Module for Package Hub 15 SP3 | All versions | 65.1-150200.4.5.1 |
| `icu` | SUSE:Linux Enterprise Module for Package Hub 15 SP4 | All versions | 65.1-150200.4.5.1 |
| `icu` | SUSE:Linux Enterprise Server 12 SP5 | All versions | 52.1-8.13.1 |
| `icu` | SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 52.1-8.13.1 |
| `icu` | SUSE:Linux Enterprise Software Development Kit 12 SP5 | All versions | 52.1-8.13.1 |
| `icu` | SUSE:Linux Enterprise Workstation Extension 12 SP5 | All versions | 52.1-8.13.1 |
| `icu` | openSUSE:Leap 15.3 | All versions | 60.2-150000.3.12.1 |
| `icu` | openSUSE:Leap 15.3 | All versions | 65.1-150200.4.5.1 |
| `icu` | openSUSE:Leap 15.4 | All versions | 60.2-150000.3.12.1 |
| `icu` | openSUSE:Leap 15.4 | All versions | 65.1-150200.4.5.1 |
| `icu` | openSUSE:Leap Micro 5.2 | All versions | 65.1-150200.4.5.1 |

Products: Debian Debian Linux, Unicode International Components for Unicode.

## How do I fix CVE-2020-21913?

Apply the vendor's patch.

## Is CVE-2020-21913 being exploited?

There is no known exploitation of CVE-2020-21913 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-21913 and fix it if it is affected.

What it is: CVE-2020-21913 is a medium-severity use after free vulnerability in Debian Debian Linux, published on 20 Sep 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-21913 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2020-21913/ (Markdown: https://insights.sbomify.com/CVE-2020-21913/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-21913
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-21913
- OSV: https://osv.dev/vulnerability/CVE-2020-21913

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-21913/
Summaries are generated and may contain mistakes; the official description above is the record.