# CVE-2020-13962: Denial of service in n/a

> Mishandling of OpenSSL error queue in Qt allows attackers to cause denial of service by disconnecting unrelated TLS sessions.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Jun 2020
- **Updated:** 4 Aug 2024
- **Also known as:** AZL-6835, DEBIAN-CVE-2020-13962, GHSA-c4xh-w73g-qgf6, MGASA-2021-0200, SUSE-SU-2020:2357-1, UBUNTU-CVE-2020-13962, openSUSE-SU-2020:1319-1, openSUSE-SU-2024:11742-1

## What is CVE-2020-13962?

CVE-2020-13962 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 8 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Qt 5.12.2 through 5.14.2, as used in unofficial builds of Mumble 1.3.0 and other products, mishandles OpenSSL's error queue, which can cause a denial of service to QSslSocket users. Because errors leak in unrelated TLS sessions, an unrelated session may be disconnected when any handshake fails. (Mumble 1.3.1 is not affected, regardless of the Qt version.)

## Which versions are affected by CVE-2020-13962?

It affects 4 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libqt5-qtbase` | SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 5.12.7-4.3.1 |
| `libqt5-qtbase` | SUSE:Linux Enterprise Module for Desktop Applications 15 SP2 | All versions | 5.12.7-4.3.1 |
| `libqt5-qtbase` | openSUSE:Leap 15.2 | All versions | 5.12.7-lp152.3.3.1 |
| `libqt5-qtbase` | openSUSE:Tumbleweed | All versions | 5.15.2+kde268-2.1 |

Products: Fedoraproject Fedora, Mumble Mumble, Opensuse Leap, Qt Qt.

## How do I fix CVE-2020-13962?

Upgrade to a fixed version.

## Is CVE-2020-13962 being exploited?

There is no known exploitation of CVE-2020-13962 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-13962 and fix it if it is affected.

What it is: CVE-2020-13962 is a high-severity denial of service vulnerability in Fedoraproject Fedora, published on 8 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-13962 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2020-13962/ (Markdown: https://insights.sbomify.com/CVE-2020-13962/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-13962
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-13962
- OSV: https://osv.dev/vulnerability/CVE-2020-13962

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-13962/
Summaries are generated and may contain mistakes; the official description above is the record.