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Vulnerability · Published Sep 7, 2026 · Assigned by EEF

CVE-2026-82753Unauthenticated authorize requests create unbounded, never-expiring CIMD client rows and cache entries in ash_authentication_oauth2_server

High 8.2

In plain English

A high-severity resource allocation without limits in ash_authentication_oauth2_server from ash-project. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 52% of all known vulnerabilities).

Severity (CVSS 4.0)8.2High
Exploit odds (30 days)0.7%top 48.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Allocation of Resources Without Limits or Throttling vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to exhaust database storage and memory. The /authorize endpoint is unauthenticated by design. With Client ID Metadata Documents enabled, resolve_client/3 in AshAuthentication.Oauth2Server.CIMD fetches the document for each new URL-shaped client_id and upserts a client row, with no cap on the number of rows, no expiry or garbage collection, and no length bound on the fetched fields; the document was also placed in CIMD.Cache before validation, so even rejected documents held cache memory until their TTL. An attacker serving valid documents at many distinct URLs creates one permanent client row per URL, each able to carry multi-megabyte strings, growing storage and memory without bound. This issue affects ash_authentication_oauth2_server: from 0.3.0 before 0.3.1.

Affected products (as reported)

VendorProductVersions
ash-project ash_authentication_oauth2_server 0.3.0 – before 0.3.1
ash-project ash_authentication_oauth2_server e713a9ba816761140c226e2ca55b75c0b93f5984 – before 45e24f69e0f95d67413e2508acc2264156acb5ac

Weakness: CWE-770 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References