---
id: CVE-2026-82753
title: >-
  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 …
summary: >-
  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 …
severity: high
cvss: 8.2
cvssVector: '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'
cwe:
  - CWE-770
vendor: ash-project
product: ash_authentication_oauth2_server
affected:
  - ash_authentication_oauth2_server >= 0.3.0 < 0.3.1
  - >-
    ash-project/ash_authentication_oauth2_server >=
    e713a9ba816761140c226e2ca55b75c0b93f5984 <
    45e24f69e0f95d67413e2508acc2264156acb5ac
published: '2026-09-07'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T15:18:50.157'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82753'
references:
  - url: 'https://cna.erlef.org/cves/CVE-2026-82753.html'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/ash-project/ash_authentication_oauth2_server/commit/45e24f69e0f95d67413e2508acc2264156acb5ac
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: >-
      https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-9pv3-wxjm-f846
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
  - url: 'https://osv.dev/vulnerability/EEF-CVE-2026-82753'
    label: 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-08T14:39:20.932056Z'
cvssSource: cna
epss: 0.0066
epssPercentile: 0.49441
ingestedAt: '2026-09-08T15:33:26.980Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.