CVE-2026-59279Network attack vector

Unbounded persistent session allocation via repeated initialize requests

Published Aug 21, 2026 · Updated Aug 21, 2026

Denial of service in Spring AI 2.0.0 allows remote attackers to exhaust server memory through unauthenticated MCP initialization requests. The WebFlux and WebMvc Streamable HTTP transports retain every session created by initialize requests without a session cap or eviction policy. Because client authentication is disabled by default, repeated remote requests can grow the session store until memory exhaustion interrupts service for all legitimate clients.

CVSS severity7.5
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Spring AI 2.0.0 allows remote attackers to exhaust server memory through unauthenticated MCP initialization requests. The WebFlux and WebMvc Streamable HTTP transports retain every session created by initialize requests without a session cap or eviction policy. Because client authentication is disabled by default, repeated remote requests can grow the session store until memory exhaustion interrupts service for all legitimate clients.

The record

CVE
CVE-2026-59279
Published
Aug 21, 2026
Updated
Aug 21, 2026
Vendor
Spring
Product
Spring AI
Classifications
CWE-770, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 21, 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=2.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Spring · Spring AIversion=2.0.0

Published CVSS scores

7.5VMware CNACVSS: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 exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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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