CVE-2026-59303Network attack vector

Unbounded resource allocation via dynamic destination cache

Published Aug 27, 2026 · Updated Aug 27, 2026

Unbounded resource allocation in affected Spring Cloud Stream releases allows attackers to grow the dynamic destination cache. StreamBridge creates and caches an output binding when send receives an unknown destination, but the affected cache does not enforce its configured maximum. Spring has not published how attackers control destination names or how cache growth produces the reported confidentiality and integrity effects.

CVSS severity3.1
Low
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unbounded resource allocation in affected Spring Cloud Stream releases allows attackers to grow the dynamic destination cache. StreamBridge creates and caches an output binding when send receives an unknown destination, but the affected cache does not enforce its configured maximum. Spring has not published how attackers control destination names or how cache growth produces the reported confidentiality and integrity effects.

The record

CVE
CVE-2026-59303
Published
Aug 27, 2026
Updated
Aug 27, 2026
Vendor
Spring
Product
Spring Cloud Stream
Classifications
CWE-770
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Aug 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 27, 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=4.2.0 <=4.2.6
  2. Affected versionversion=4.3.0 <=4.3.3
  3. Affected versionversion=5.0.0 <=5.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Spring · Spring Cloud Streamversion=4.2.0 <=4.2.6; version=4.3.0 <=4.3.3; version=5.0.0 <=5.0.2

Published CVSS scores

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

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling

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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