# CVE-2021-3629: undertow: A flaw was found in Undertow

CVE-2021-3629 is fixed in undertow on 1 platform by DEBIAN-CVE-2021-3629 (version 2.2.12-1), released May 24, 2022. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-3629
- Priority: Routine
- CVSS: 5.9 (medium)
- EPSS: 0.0132
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 24, 2022

## Description

A flaw was found in Undertow. A potential security issue in flow control handling by the browser over http/2 may potentially cause overhead or a denial of service in the server. The highest threat from this vulnerability is availability. This flaw affects Undertow versions prior to 2.0.40.Final and prior to 2.2.11.Final.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | undertow Debian 14 | 2.2.12-1 | [DEBIAN-CVE-2021-3629](https://patchblox.com/security/data/fix/linux/debian-cve-2021-3629.md) | May 24, 2022 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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