CVE-2026-81315Public exploitNetwork attack vector

Cross-site MCP tool invocation via spoofed proxy header

Published Aug 31, 2026 · Updated Aug 31, 2026

Origin validation error in Ash AI allows remote attackers to invoke local MCP tools through an attacker-controlled web page. AshAi.Mcp.Server's origin_allowed?/3 compares the attacker-controlled Host value and trusts raw X-Forwarded-Proto as proof of HTTPS. The default allowed_origins setting and a user's visit to the page are required; accepted requests run with that user's actor.

CVSS severity7.4
High
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin validation error in Ash AI allows remote attackers to invoke local MCP tools through an attacker-controlled web page. AshAi.Mcp.Server's origin_allowed?/3 compares the attacker-controlled Host value and trusts raw X-Forwarded-Proto as proof of HTTPS. The default allowed_origins setting and a user's visit to the page are required; accepted requests run with that user's actor.

The record

CVE
CVE-2026-81315
Published
Aug 31, 2026
Updated
Aug 31, 2026
Vendor
Ash Framework
Product
Ash AI
Classifications
CWE-346, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.8.0 <1.0.0
  2. Affected versionversion=c94f0b17fbe252f68755ba512678586164ba6139 <28af68d73134df0b8fb3aa6ab03e8fd795b07c21

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Ash Framework · Ash AIversion=0.8.0 <1.0.0; version=c94f0b17fbe252f68755ba512678586164ba6139 <28af68d73134df0b8fb3aa6ab03e8fd795b07c21

Published CVSS scores

7.4GitHubCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/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 exploitPublished

Weakness, pattern, technique

CWE-346Origin Validation Error
T1189Drive-by Compromise

Public exploit references

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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