CVE-2026-82757Network attack vector

Internal service access via IPv6 classification bypass

Published Sep 7, 2026 · Updated Sep 8, 2026

SSRF in the CIMD metadata fetcher in Ash Project ash_authentication_oauth2_server 0.3.0 allows remote attackers to reach internal services. The public_ip?/1 policy treats IPv4-compatible, SIIT IPv4-translated, and site-local IPv6 addresses as public, letting pinned AAAA records bypass destination filtering. Exploitation requires CIMD to be enabled and attacker control of a client metadata URL and its DNS; the server can then retrieve responses from internal or loopback services.

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

SSRF in the CIMD metadata fetcher in Ash Project ash_authentication_oauth2_server 0.3.0 allows remote attackers to reach internal services. The public_ip?/1 policy treats IPv4-compatible, SIIT IPv4-translated, and site-local IPv6 addresses as public, letting pinned AAAA records bypass destination filtering. Exploitation requires CIMD to be enabled and attacker control of a client metadata URL and its DNS; the server can then retrieve responses from internal or loopback services.

The record

CVE
CVE-2026-82757
Published
Sep 7, 2026
Updated
Sep 8, 2026
Vendor
Ash Project
Product
ash_authentication_oauth2_server
Classifications
CWE-918, CAPEC-664, T1190
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=0.3.0 <0.3.1
  2. Affected versionversion=e713a9ba816761140c226e2ca55b75c0b93f5984 <268b591261a3473ab9b87272963e4dd2fd99d972

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Ash Project · ash_authentication_oauth2_serverversion=0.3.0 <0.3.1; version=e713a9ba816761140c226e2ca55b75c0b93f5984 <268b591261a3473ab9b87272963e4dd2fd99d972

Published CVSS scores

6.3Erlang Ecosystem Foundation CNACVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/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-918Server-Side Request Forgery (SSRF)
CAPEC-664Server Side Request Forgery
T1190Exploit Public-Facing Application

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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