CVE-2026-9053Network attack vector

Local file disclosure via hidden upload defaults

Published May 22, 2026 · Updated May 22, 2026

Information disclosure in Mothra in 9front allows remote attackers to read local files through crafted HTML upload forms. The rdform() routine in /sys/src/cmd/mothra/forms.c accepts a website-supplied value attribute for a file input as a local pathname, including when the control is hidden, and submission uploads the named file. The target must actively open the attacker's page and submit the form; the demonstrated consequence is disclosure of files accessible to the Mothra process, not local modification or service interruption.

CVSS severityUnavailable
Unscored
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

Information disclosure in Mothra in 9front allows remote attackers to read local files through crafted HTML upload forms. The rdform() routine in /sys/src/cmd/mothra/forms.c accepts a website-supplied value attribute for a file input as a local pathname, including when the control is hidden, and submission uploads the named file. The target must actively open the attacker's page and submit the form; the demonstrated consequence is disclosure of files accessible to the Mothra process, not local modification or service interruption.

The record

CVE
CVE-2026-9053
Published
May 22, 2026
Updated
May 22, 2026
Vendor
9front
Product
9front
Classifications
CWE-434, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 22, 2026CVE publishedPublication date reported by the CVE source.
  2. May 22, 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=f04e113279274526a8dae34de373027b68921fbf <d145acc9ef0da47131af6ad94e87264e04870d47

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

9front · 9frontversion=f04e113279274526a8dae34de373027b68921fbf <d145acc9ef0da47131af6ad94e87264e04870d47

Published CVSS scores

6.99frontCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:P

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-434Unrestricted Upload of File with Dangerous Type
T1204.001Malicious Link

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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