Undertow vulnerable to Dos via Large AJP request

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2022-2053: 1.09% estimated exploitation activity in the next 30 days; percentile 65.49 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

When a POST request comes through AJP and the request exceeds the max-post-size limit (maxEntitySize), Undertow's AjpServerRequestConduit implementation closes a connection without sending any response to the client/proxy. This behavior results in that a front-end proxy marking the backend worker (application server) as an error state and not forward requests to the worker for a while. In modcluster, this continues until the next STATUS request (10 seconds intervals) from the application server updates the server state. So, in the worst case, it can result in "All workers are in error state" and modcluster responds "503 Service Unavailable" for a while (up to 10 seconds). In modproxybalancer, it does not forward requests to the worker until the "retry" timeout passes. However, luckily, modproxybalancer has "forcerecovery" setting (On by default; this parameter can force the immediate recovery of all workers without considering the retry parameter of the workers if all workers of a…

Published by the source

6 Aug 2022, 00:00 UTC

Last modified by the source

30 Jan 2023, 05:06 UTC

Source last checked

26 Oct 2026, 16:02 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-95rf-557x-44g5

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# Patch Next advisory brief: CVE-2022-2053

Advisory: Undertow vulnerable to Dos via Large AJP request
IDs: CVE-2022-2053, GHSA-95rf-557x-44g5
Record: https://patchnext.com/advisories/cve-2022-2053 (revision 1, source checked 26 Oct 2026, 16:02 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: io.undertow:undertow-core 2.3.0.Alpha2, 2.2.19.Final. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven io.undertow:undertow-core: affected < 2.2.19.Final; >= 2.3.0.Alpha1, <= 2.3.0.Alpha1; fixed in 2.2.19.Final, 2.3.0.Alpha2

## Suggested inspection (read-only)
- Maven io.undertow:undertow-core: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on io.undertow:undertow-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-95rf-557x-44g5 (GitHub-reviewed advisory GHSA-95rf-557x-44g5 lists affected ranges: Maven io.undertow:undertow-core >=0 =2.3.0.Alpha1 <=2.3.0.Alpha1)

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