CVE-2026-43507Public exploitNetwork attack vector

Unauthenticated service interruption via XML stanza amplification

Published May 1, 2026 · Updated May 1, 2026

Resource exhaustion in Prosody before 0.12.6 and 1.0.0 through 13.0.4 allows remote attackers to interrupt service via XML stanzas. The c2s and s2s stream parsers accept unauthenticated XML stanzas whose serialized size understates the memory consumed by their structure. Per-connection rate limits do not bound this amplification, and concurrent unauthenticated connections can exhaust memory and interrupt the server.

CVSS severity7.5
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Prosody before 0.12.6 and 1.0.0 through 13.0.4 allows remote attackers to interrupt service via XML stanzas. The c2s and s2s stream parsers accept unauthenticated XML stanzas whose serialized size understates the memory consumed by their structure. Per-connection rate limits do not bound this amplification, and concurrent unauthenticated connections can exhaust memory and interrupt the server.

The record

CVE
CVE-2026-43507
Published
May 1, 2026
Updated
May 1, 2026
Vendor
Prosody IM
Product
Prosody
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <0.12.6
  2. Affected versionversion=1.0.0 <13.0.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Prosody IM · Prosodyversion=0 <0.12.6; version=1.0.0 <13.0.5

Published CVSS scores

7.5Prosody IMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.3MITRECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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