# CVE-2021-28165: Jetty vulnerable to incorrect handling of invalid large TLS frame, exhausting CPU resources

> Attackers can cause 100% CPU usage and service disruption in Eclipse Jetty by sending large invalid TLS frames.

- **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:** 1 Apr 2021
- **Updated:** 27 Aug 2025
- **Also known as:** BIT-jenkins-2021-28165, CLEANSTART-2026-BW99256, DEBIAN-CVE-2021-28165, GHSA-26vr-8j45-3r4w, UBUNTU-CVE-2021-28165

## What is CVE-2021-28165?

CVE-2021-28165 is a high-severity denial of service vulnerability in Eclipse Jetty, published on 1 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Eclipse Jetty 7.2.2 to 9.4.38, 10.0.0.alpha0 to 10.0.1, and 11.0.0.alpha0 to 11.0.1, CPU usage can reach 100% upon receiving a large invalid TLS frame.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions), CWE-551 (Incorrect Behavior Order: Authorization Before Parsing and Canonicalization), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2021-28165?

7 open source packages ship an affected version, including org.eclipse.jetty:jetty-server and jenkins. It affects 21 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.eclipse.jetty:jetty-server` | Maven | From 10.0.0 | 10.0.2 |
| `org.eclipse.jetty:jetty-server` | Maven | From 10.0.0 | 10.0.2 |
| `org.eclipse.jetty:jetty-server` | Maven | From 11.0.0 | 11.0.2 |
| `org.eclipse.jetty:jetty-server` | Maven | From 11.0.0 | 11.0.2 |
| `org.eclipse.jetty:jetty-server` | Maven | From 7.2.2 | 9.4.39 |
| `org.eclipse.jetty:jetty-server` | Maven | From 7.2.2 | 9.4.39 |
| `jenkins` | Bitnami | All versions | 2.286.0 |

Products: Eclipse Jetty, Jenkins Jenkins, Netapp Cloud Manager, Netapp E-Series Performance Analyzer, Netapp E-Series Santricity Os Controller, Netapp E-Series Santricity Storage, Netapp E-Series Santricity Web Services, Netapp Ontap Tools, Netapp Santricity Cloud Connector, Netapp Santricity Web Services Proxy, Netapp Snapcenter, Netapp Storage Replication Adapter for Clustered Data Ontap, Netapp Vasa Provider for Clustered Data Ontap, Oracle Autovue for Agile Product Lifecycle Management, Oracle Communications Cloud Native Core Policy, Oracle Communications Element Manager, Oracle Communications Services Gatekeeper, Oracle Communications Session Report Manager, Oracle Communications Session Route Manager, Oracle Rest Data Services and 1 more.

## How do I fix CVE-2021-28165?

Upgrade org.eclipse.jetty:jetty-server to a fixed version for your release line: 10.0.2, 11.0.2 or 9.4.39.

## Is CVE-2021-28165 being exploited?

There is no known exploitation of CVE-2021-28165 in the wild and no public exploit code.

Public exploit code:

- https://github.com/uthrasri/CVE-2021-28165 (github_poc): https://github.com/uthrasri/CVE-2021-28165

## Other vulnerabilities in Eclipse Jetty

- [CVE-2016-4800](https://insights.sbomify.com/CVE-2016-4800/): Jetty contains an alias issue that could allow unauthenticated remote code execution due to specially crafted request (critical 9.8)
- [CVE-2019-17638](https://insights.sbomify.com/CVE-2019-17638/): Operation on a Resource after Expiration or Release in Jetty Server (critical 9.4)
- [CVE-2018-12538](https://insights.sbomify.com/CVE-2018-12538/): Access and integrity issue within Eclipse Jetty (high 8.8)
- [CVE-2026-10050](https://insights.sbomify.com/CVE-2026-10050/): Digest authentication lossy encoding (high 8.7)
- [CVE-2025-5115](https://insights.sbomify.com/CVE-2025-5115/): MadeYouReset HTTP/2 vulnerability (high 7.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-28165 and fix it if it is affected.

What it is: CVE-2021-28165 is a high-severity denial of service vulnerability in Eclipse Jetty, published on 1 Apr 2021. 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-2021-28165 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.eclipse.jetty:jetty-server (Maven): affected from 10.0.0; fixed in 10.0.2
- org.eclipse.jetty:jetty-server (Maven): affected from 10.0.0; fixed in 10.0.2
- org.eclipse.jetty:jetty-server (Maven): affected from 11.0.0; fixed in 11.0.2
- org.eclipse.jetty:jetty-server (Maven): affected from 11.0.0; fixed in 11.0.2
- org.eclipse.jetty:jetty-server (Maven): affected from 7.2.2; fixed in 9.4.39
- org.eclipse.jetty:jetty-server (Maven): affected from 7.2.2; fixed in 9.4.39
- jenkins (Bitnami): affected all versions; fixed in 2.286.0

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-2021-28165/ (Markdown: https://insights.sbomify.com/CVE-2021-28165/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-28165
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-28165
- OSV: https://osv.dev/vulnerability/CVE-2021-28165

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-28165/
Summaries are generated and may contain mistakes; the official description above is the record.