dbcve.org
JamesApplication · Apache

CVE-2021-40111

MEDIUM · 6.5 CVSS v3.1 Published 2022-01-04
Fix available
A fix is available. Upgrade to 3.6.1 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In Apache James IMAP server, specially crafted APPEND and STATUS IMAP commands trigger infinite loops in the parser, causing excessive CPU computation and OutOfMemory exceptions. This results in denial of service. The attacker requires valid IMAP authentication to exploit this vulnerability.

MitigationUpgrade Apache James to version 3.6.1 or higher to patch the vulnerable IMAP parsing stack.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
JamesApplication
Affected:< 3.6.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Apache James installation and version
    Run 'java -jar james-*.jar --version' or check the JAR file name, or look for James-specific files in the installation directory (e.g., bin/james startup scripts, james-server-*.jar files)
    Affected if The installed version is Apache James and the version is below 3.6.1
  2. Verify IMAP service is enabled
    Check James configuration files (e.g., conf/james-server.xml or conf/imapserver.xml) for the IMAP protocol enabled setting, or check if port 143 or 993 is listening
    Affected if IMAP protocol is enabled and listening on the server
  3. Confirm authentication is available
    Check if the IMAP service accepts authentication connections, or review user database configuration in James conf files
    Affected if IMAP authentication is configured and functional, allowing valid users to connect
  4. Review IMAP logs for anomalous commands
    Examine James IMAP server logs (typically in logs/ directory) for APPEND or STATUS commands that may have caused excessive CPU or memory issues, looking for patterns that could indicate exploitation attempts
    Affected if Logs show prolonged parsing operations, thread dumps with stuck IMAP parser threads, or OutOfMemory errors related to IMAP command processing

You are affected if you are running Apache James version below 3.6.1 with IMAP service enabled and accessible to authenticated users.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 3.6.1 or later
Fixed in 3.6.1
Interim mitigation

Upgrade Apache James to version 3.6.1 or higher to patch the vulnerable IMAP parsing stack.

Recommended fix High confidence

Apache James 3.6.1 or later

  1. Backup your current Apache James configuration and mail data directory
  2. Stop the running Apache James server
  3. Download Apache James 3.6.1 or a later stable release from the official Apache James distribution (https://james.apache.org/download.cgi)
  4. Replace the existing James installation with the new version, preserving your configuration files
  5. Start the Apache James server
  6. Verify the server is running and test IMAP functionality with both APPEND and STATUS commands to confirm the infinite loop vulnerability is resolved

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in James Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-40111 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data