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Prosody CVE-2021-32918

HIGH
Uncontrolled Resource Consumption (CWE-400)
2021-05-13 cve@mitre.org
7.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Resource consumption limits
MITRE ATT&CK

1 technique across 1 tactic: Impact

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

A remote attacker could cause denial of service by exhausting system resources by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 2.1% exploitation probability (EPSS)

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AnalysisAI

An issue was discovered in Prosody before 0.11.9. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Implement rate limiting, set resource quotas, validate input sizes, use timeouts.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Uncontrolled Resource Consumption (CWE-400), which allows attackers to cause denial of service by exhausting system resources. An issue was discovered in Prosody before 0.11.9. Default settings are susceptible to remote unauthenticated denial-of-service (DoS) attacks via memory exhaustion when running under Lua 5.2 or Lua 5.3. Affected products include: Prosody, Debian Debian Linux, Fedoraproject Fedora. Version information: before 0.11.9..

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionNVD

An issue was discovered in Prosody before 0.11.9. Default settings are susceptible to remote unauthenticated denial-of-service (DoS) attacks via memory exhaustion when running under Lua 5.2 or Lua 5.3.

Threat Intelligence Overview

EPSS Score
2.1%
Top 20% exploitable
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 2.1%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

40
Low Medium High Critical
KEV: 0
EPSS: +2
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)NVD

cpe:2.3:a:prosody:prosody:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
CVE-2014-2744 HIGH POC
7.8 Apr 11

plugins/mod_compression.lua in (1) Prosody before 0.9.4 and (2) Lightwitch Metronome through 3.4 negotiates stream compr

CVE-2022-0217 HIGH POC
7.5 Aug 26

It was discovered that an internal Prosody library to load XML based on libexpat does not properly restrict the XML feat

CVE-2021-37601 HIGH POC
7.5 Jul 30

muc.lib.lua in Prosody 0.11.0 through 0.11.9 allows remote attackers to obtain sensitive information (list of admins, me

CVE-2020-8086 CRITICAL
9.8 Jan 28

The mod_auth_ldap and mod_auth_ldap2 Community Modules through 2020-01-27 for Prosody incompletely verify the XMPP addre

CVE-2018-10847 HIGH
8.8 Jul 30

prosody before versions 0.10.2, 0.9.14 is vulnerable to an Authentication Bypass. Rated high severity (CVSS 8.8), this v

CVE-2014-2745 HIGH
7.8 Apr 11

Prosody before 0.9.4 does not properly restrict the processing of compressed XML elements, which allows remote attackers

CVE-2016-1232 HIGH
7.5 Jan 12

The mod_dialback module in Prosody before 0.9.9 does not properly generate random values for the secret token for server

CVE-2021-32920 HIGH
7.5 May 13

Prosody before 0.11.9 allows Uncontrolled CPU Consumption via a flood of SSL/TLS renegotiation requests. Rated high seve

CVE-2021-32919 HIGH
7.5 May 13

An issue was discovered in Prosody before 0.11.9. Rated high severity (CVSS 7.5), this vulnerability is remotely exploit

CVE-2026-43505 MEDIUM
6.5 May 01

Unauthenticated traffic relay vulnerability in Prosody mod_proxy65 module allows network attackers to bypass access cont

CVE-2026-43504 MEDIUM
6.5 May 01

Improper access control in Prosody's mod_proxy65 module allows unauthenticated relaying of traffic when the module enter

CVE-2016-1231 MEDIUM
5.9 Jan 12

Directory traversal vulnerability in the HTTP file-serving module (mod_http_files) in Prosody 0.9.x before 0.9.9 allows

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