CVE-2026-80347Public exploitNetwork attack vector

Internal data disclosure via IPv6 bracket bypass

Published Aug 26, 2026 · Updated Aug 26, 2026

SSRF in kazuph MCP Fetch 1.6.3 and earlier allows remote attackers to read internal responses via bracketed IPv6 literals. The isSafeUrl guard passes the bracketed hostname to net.isIP, treats its zero result as a DNS name, and reports it safe when resolution returns no addresses. Control of the model-supplied fetch target is required; IPv4-mapped literals also expose loopback, private, and link-local metadata services.

CVSS severity8.7
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in kazuph MCP Fetch 1.6.3 and earlier allows remote attackers to read internal responses via bracketed IPv6 literals. The isSafeUrl guard passes the bracketed hostname to net.isIP, treats its zero result as a DNS name, and reports it safe when resolution returns no addresses. Control of the model-supplied fetch target is required; IPv4-mapped literals also expose loopback, private, and link-local metadata services.

The record

CVE
CVE-2026-80347
Published
Aug 26, 2026
Updated
Aug 26, 2026
Vendor
kazuph
Product
MCP Fetch
Classifications
CWE-918, T1552.005
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 26, 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 <=1.6.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

kazuph · MCP Fetchversion=0 <=1.6.3

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
7.5VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A: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-918Server-Side Request Forgery (SSRF)
T1552.005Cloud Instance Metadata API

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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