CVE-2025-6203Network attack vector

Unauthenticated denial of service via unbounded JSON complexity

Published Aug 28, 2025 · Updated Oct 23, 2025

Denial of service in HashiCorp Vault and Vault Enterprise allows remote attackers to make servers unresponsive via complex JSON payloads. The HTTP handler accepts payloads within max_request_size without bounding JSON nesting depth, string length, object entries, or array elements, driving excessive CPU and memory use during audit processing. No authentication or user interaction is required; successful exploitation can stop the server from responding when audit processing times out.

CVSS severity7.5
High
EPSS probability0.70%
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 HashiCorp Vault and Vault Enterprise allows remote attackers to make servers unresponsive via complex JSON payloads. The HTTP handler accepts payloads within max_request_size without bounding JSON nesting depth, string length, object entries, or array elements, driving excessive CPU and memory use during audit processing. No authentication or user interaction is required; successful exploitation can stop the server from responding when audit processing times out.

The record

CVE
CVE-2025-6203
Published
Aug 28, 2025
Updated
Oct 23, 2025
Vendor
HashiCorp
Product
Vault
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 23, 2025Record 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=1.15.0 <1.21.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

HashiCorp · Vaultversion=1.15.0 <1.21.0
HashiCorp · Vault Enterpriseversion=1.15.0 <1.21.2 changes=[{"at":"1.20.5","status":"unaffected"},{"at":"1.19.11","status":"unaffected"},{"at":"1.16.27","status":"unaffected"}]

Published CVSS scores

7.5GitHub Advisory DatabaseCVSS: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.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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