CVE-2026-81315

HIGHPre-NVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 91% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this weekElevated
7.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.4Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Origin Validation Error vulnerability in ash-project ash_ai allows a malicious web page to bypass the MCP server's DNS-rebinding protection and issue cross-site requests to a user's local MCP server with that user's actor.

In AshAi.Mcp.Server, with the default allowed_origins: nil, origin_allowed?/3 accepts an origin when uri.host == conn.host and the forwarded scheme is https. Both values are attacker-controlled: conn.host comes from the Host header and the scheme is read from the raw x-forwarded-proto header with no trusted-proxy check. Under DNS rebinding the browser sends the attacker's origin and a matching host, and page JavaScript may set X-Forwarded-Proto: https, so the check passes with no TLS or proxy involved. The fix trusts only localhost origins by default; other origins require an explicit allowed_origins allowlist.

This issue affects ash_ai: from 0.8.0 before 1.0.0.

CVSS v3
7.4
EG Score
7.4(medium)
EG Risk
49(Track*)
EG Risk 49/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity74% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
9%
KEV
Not listed

Published

August 31, 2026

Last Modified

September 1, 2026

Advisory Details (4)

Auto-updated Aug 31, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit.
github_commit Patch Available

commit 28af68d73134 (ash-project/ash_ai)

Patch available: ash-project/ash_ai v1.0.0 (contains commit 28af68d73134)

https://github.com/ash-project/ash_ai/commit/28af68d73134df0b8fb3aa6ab03e8fd795b07c21
generic

OSV - Open Source Vulnerabilities

https://osv.dev/vulnerability/EEF-CVE-2026-81315
generic

CVE-2026-81315

https://cna.erlef.org/cves/CVE-2026-81315.html
github Patch Available🟡 PoC Available

Origin-validation bypass in `AshAi.Mcp.Server` in AshAi via an X-Forwarded-Proto header enables DNS-rebinding CSRF · Advisory · ash-project/ash_ai · GitHub

https://github.com/ash-project/ash_ai/security/advisories/GHSA-c92r-f3rr-q49h

Affected Packages

(1 across 1 ecosystem)
Hex(1)
PackageVulnerable rangeFixed inDependents
ash_ai0.8.0, 0.8.1, 0.8.21.0.0—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 10× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-01 16:07 UTCEG score recompute
  2. 2026-09-01 13:54 UTCEPSS rescore
  3. 2026-09-01 04:40 UTCEPSS rescore
  4. 2026-09-01 04:40 UTCEPSS rescore
  5. 2026-09-01 04:14 UTCEG score recompute
  6. 2026-08-31 16:25 UTCEG score recompute
  7. 2026-08-31 16:15 UTCEG score recompute
  8. 2026-08-31 01:37 UTCEG score recompute
  9. 2026-08-31 01:05 UTCEG score recompute
  10. 2026-08-31 01:04 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-81315?
CVE-2026-81315 is a high vulnerability published on August 31, 2026. Origin Validation Error vulnerability in ash-project ash_ai allows a malicious web page to bypass the MCP server's DNS-rebinding protection and issue cross-site requests to a user's local MCP server with that user's actor. In AshAi.Mcp.Server, with the default allowedorigins: nil, originallowed?/3…
When was CVE-2026-81315 disclosed?
CVE-2026-81315 was first published in the National Vulnerability Database on August 31, 2026, with the most recent update on September 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81315 actively exploited?
CVE-2026-81315 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 91.3% of all scored CVEs.
What is the CVSS score of CVE-2026-81315?
CVE-2026-81315 has a CVSS v3 base score of 7.4 (NVD).
How do I remediate CVE-2026-81315?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81315, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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