Infinite Loop in Apache James

Exploitation

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

CVSS

not scored

EPSS

• CVE-2021-40111: 2.19% estimated exploitation activity in the next 30 days; percentile 82.47 (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.

In Apache James, while fuzzing with Jazzer the IMAP parsing stack, we discover that crafted APPEND and STATUS IMAP command could be used to trigger infinite loops resulting in expensive CPU computations and OutOfMemory exceptions. This can be used for a Denial Of Service attack. The IMAP user needs to be authenticated to exploit this vulnerability. This affected Apache James prior to version 3.6.1. This vulnerability had been patched in Apache James 3.6.1 and higher. We recommend the upgrade.

Published by the source

8 Jan 2022, 00:40 UTC

Last modified by the source

3 Feb 2023, 05:03 UTC

Source last checked

26 Oct 2026, 16:10 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-fqgw-6qj5-8hmp

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# Patch Next advisory brief: CVE-2021-40111

Advisory: Infinite Loop in Apache James
IDs: CVE-2021-40111, GHSA-fqgw-6qj5-8hmp
Record: https://patchnext.com/advisories/cve-2021-40111 (revision 1, source checked 26 Oct 2026, 16:10 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.apache.james:james-server 3.6.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.james:james-server: affected < 3.6.1; fixed in 3.6.1

## Suggested inspection (read-only)
- Maven org.apache.james:james-server: 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 org.apache.james:james-server.
- 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-fqgw-6qj5-8hmp (GitHub-reviewed advisory GHSA-fqgw-6qj5-8hmp lists affected ranges: Maven org.apache.james:james-server >=0 <3.6.1)

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