# CVE-2026-82757 — ash-project ash_authentication_oauth2_server

> As of 2026-09-08, CVE-2026-82757 is a Medium-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in ash-project ash_authentication_oauth2_server, CVSS v4.0 6.3, EPSS 0.3% (30.1th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-82757 as of 2026-09-08; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-09-08

## What is CVE-2026-82757?

Server-Side Request Forgery (SSRF) vulnerability in ash-project ash_authentication_oauth2_server allows an attacker who controls a client metadata URL and its DNS to make the server connect to internal or loopback addresses. public_ip?/1 in AshAuthentication.Oauth2Server.CIMD.ReqFetcher enforces the outbound policy for CIMD metadata fetches. It classified several address forms as publicly routable that are not: IPv4-compatible ::/96 (for example ::127.0.0.1), SIIT IPv4-translated ::ffff:0:0:0/96, and deprecated site-local fec0::/10. A returned AAAA record in one of these ranges passed the policy, so a fetch pinned to that address reached space the policy was meant to block. This issue affects ash_authentication_oauth2_server: from 0.3.0 before 0.3.1.

The record classifies CVE-2026-82757 under weakness class [CWE-918](https://intel.threadlinqs.com/cwe/CWE-918). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 28 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 6.3 — Medium (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N`)
- **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 30.1% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-07, last modified 2026-09-08

## Is CVE-2026-82757 being exploited?

It currently carries a trending score of 37 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [ash-project](https://intel.threadlinqs.com/vendors/ash-project): ash_authentication_oauth2_server

## How to fix CVE-2026-82757

No vendor patch reference has been recorded for CVE-2026-82757 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-82757

No threat campaign in the Threadlinqs corpus currently references CVE-2026-82757, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on 2026-09-08.

**Vendor advisory and patch**

- [github.com — vendor advisory](https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-wprp-8gvj-p6cv)
- [github.com — patch](https://github.com/ash-project/ash_authentication_oauth2_server/commit/268b591261a3473ab9b87272963e4dd2fd99d972)

**Other references**

- [cna.erlef.org — related](https://cna.erlef.org/cves/CVE-2026-82757.html)
- [osv.dev — related](https://osv.dev/vulnerability/EEF-CVE-2026-82757)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-82757
Full detection coverage and IOCs for threats exploiting CVE-2026-82757 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp