CVE-2026-82755Network attack vector

Cross-tenant OAuth confusion via publicly cached metadata

Published Sep 7, 2026 · Updated Sep 8, 2026

Cache isolation failure in Ash Project ash_authentication_oauth2_server 0.1.3 through 0.3.0 allows remote attackers to confuse OAuth clients. ProtocolRouter marks tenant-specific discovery responses public for one hour without varying on a header- or Host-derived tenant, allowing a shared cache to reuse one tenant's issuer, endpoints, and key URI for another. Exposure requires a multi-tenant deployment behind such a cache and can direct authorization codes or client secrets to the wrong tenant and cause token validation against the wrong keys.

CVSS severity6.3
Medium
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cache isolation failure in Ash Project ash_authentication_oauth2_server 0.1.3 through 0.3.0 allows remote attackers to confuse OAuth clients. ProtocolRouter marks tenant-specific discovery responses public for one hour without varying on a header- or Host-derived tenant, allowing a shared cache to reuse one tenant's issuer, endpoints, and key URI for another. Exposure requires a multi-tenant deployment behind such a cache and can direct authorization codes or client secrets to the wrong tenant and cause token validation against the wrong keys.

The record

CVE
CVE-2026-82755
Published
Sep 7, 2026
Updated
Sep 8, 2026
Vendor
Ash Project
Product
ash_authentication_oauth2_server
Classifications
CWE-524, CAPEC-204
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 8, 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=0.1.3 <0.3.1
  2. Affected versionversion=99de0a1cacb5ef667c4533278b7c81ca98c00231 <768d87f70e4e97ae1d2bf1606b5bf3f4d03f24a1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Ash Project · ash_authentication_oauth2_serverversion=0.1.3 <0.3.1; version=99de0a1cacb5ef667c4533278b7c81ca98c00231 <768d87f70e4e97ae1d2bf1606b5bf3f4d03f24a1

Published CVSS scores

6.3Ash ProjectCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:L/SA: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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-524Use of Cache Containing Sensitive Information
CAPEC-204Lifting Sensitive Data Embedded in Cache

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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