VYPR
Moderate severityNVD Advisory· Published Jan 4, 2022· Updated Aug 4, 2024

Apache James IMAP parsing Denial Of Service

CVE-2021-40111

Description

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.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Crafted IMAP APPEND and STATUS commands cause infinite loops and resource exhaustion in Apache James before 3.6.1, enabling authenticated DoS attacks.

Vulnerability

In Apache James, while fuzzing with Jazzer the IMAP parsing stack, discover crafted APPEND and STATUS IMAP commands trigger infinite loops, leading to expensive CPU computations and OutOfMemory exceptions. This affects Apache James prior to version 3.6.1 [1][2][3].

Exploitation

An attacker must be authenticated as an IMAP user to exploit this vulnerability. By sending specially crafted APPEND or STATUS commands, the attacker can cause the parsing loop to never terminate [1][2].

Impact

Successful exploitation results in a Denial of Service (DoS) due to resource exhaustion, consuming excessive CPU and memory, potentially causing the mail server to become unresponsive or crash [1][2][3].

Mitigation

This vulnerability has been patched in Apache James version 3.6.1 and later. Users are strongly recommended to upgrade to the latest version. No other workarounds are documented in the available references [1][2][3].

AI Insight generated on May 21, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.

Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
org.apache.james:james-serverMaven
< 3.6.13.6.1

Affected products

10

Patches

0

No patches discovered yet.

Vulnerability mechanics

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References

4

News mentions

0

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