CVE-2026-78839Public exploitNetwork attack vector

Code execution via crafted PHAR file upload

Published Sep 4, 2026 · Updated Sep 4, 2026

Arbitrary file upload in AppNitro MachForm 30 allows remote attackers to execute code by submitting a crafted .phar file. The upload.php path accepts .phar files when a form permits that extension, stores each upload under an MD5-derived name, and leaves it retrievable for execution. Exploitation requires a public upload form that permits .phar files and discovery of the generated filename through brute-force enumeration or a separate disclosure.

CVSS severityUnavailable
Unscored
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary file upload in AppNitro MachForm 30 allows remote attackers to execute code by submitting a crafted .phar file. The upload.php path accepts .phar files when a form permits that extension, stores each upload under an MD5-derived name, and leaves it retrievable for execution. Exploitation requires a public upload form that permits .phar files and discovery of the generated filename through brute-force enumeration or a separate disclosure.

The record

CVE
CVE-2026-78839
Published
Sep 4, 2026
Updated
Sep 4, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.2Nabeel KhanCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/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.

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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

T1190Exploit Public-Facing Application

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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