# CVE-2026-82753: ash-project ash_authentication_oauth2_server unbound resource allocation in /authorize

Source: https://junglewise.ai/threats/cve-2026-82753-ash-project-ash-authentication-oauth2-server-unbound-resource  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-07. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-82753 · Severity: info · Published 2026-09-07

ash_authentication_oauth2_server is a library that provides OAuth 2.0 authentication for applications built with the Ash framework. An attacker can exploit an unprotected endpoint by providing many distinct client metadata URLs, causing the server to create unlimited database records and cache entries with no size or expiration limits, leading to denial of service through resource exhaustion.

Technologies: [Ash-Project Ash Authentication Oauth2 Server](https://junglewise.ai/threats/technologies/ash-authentication-oauth2-server). Vendors: [Ash-Project](https://junglewise.ai/threats/vendors/ash-project).

## Quick answers

**Is CVE-2026-82753 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-82753 being exploited in the wild.

**How severe is CVE-2026-82753?** Informational severity, published 7 September 2026.

**Which products and versions are affected?** Ash-Project Ash Authentication Oauth2 Server 0.3.0 before 0.3.1.

**Is there a fix for CVE-2026-82753?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-82753 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-82753?** Check whether you run Ash-Project Ash Authentication Oauth2 Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the /authorize endpoint's resolve_client/3 function within the Client ID Metadata Document (CIMD) feature. When processing an unauthenticated request, the endpoint fetches and upserts a client row for each URL-shaped client_id without enforcing any limits on the number of rows, TTL-based cleanup, or field length validation. Additionally, fetched documents are cached before validation, allowing rejected documents to consume memory until cache expiration. An attacker can exploit this by serving valid OAuth 2.0 metadata documents from many distinct URLs, with multi-megabyte strings in document fields, causing unbounded growth of database storage and in-memory cache. The issue affects versions 0.3.0 through 0.3.0; a fix is available in version 0.3.1.

## Affected products

- ash-project ash_authentication_oauth2_server 0.3.0 before 0.3.1

## Timeline

- 2026-09-07: disclosed

## References

- [https://repo.hex.pm/](https://repo.hex.pm/)
- [https://github.com/](https://github.com/)

## Related threats

- [ash-project ash_authentication_oauth2_server authentication bypass in client registration](https://junglewise.ai/threats/cve-2026-82758-ash-project-ash-authentication-oauth2-server-authentication)
- [ash-project ash_authentication_oauth2_server SSRF in metadata fetch](https://junglewise.ai/threats/cve-2026-82757-ash-project-ash-authentication-oauth2-server-ssrf-in-metadata)
- [ash-project ash_authentication_oauth2_server parameter injection in WWW-Authenticate header](https://junglewise.ai/threats/cve-2026-82756-ash-project-ash-authentication-oauth2-server-parameter-injection)
- [ash-project ash_authentication_oauth2_server cache poisoning in OAuth discovery metadata](https://junglewise.ai/threats/cve-2026-82755-ash-project-ash-authentication-oauth2-server-cache-poisoning-in)
- [ash-project ash_authentication_oauth2_server path traversal in OAuth endpoints](https://junglewise.ai/threats/cve-2026-82754-ash-project-ash-authentication-oauth2-server-path-traversal-in)