What is CVE-2026-78839?

CVE-2026-78839 is a high-severity vulnerability in N/a, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 8.1/10. Published 2026-09-04.

How severe is CVE-2026-78839?

High severity. CVSS v3 base score is 8.1 out of 10.

Is CVE-2026-78839 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Arbitrary file upload in N/a

CVE-2026-78839

An arbitrary file upload vulnerability in AppNitro MachForm v30 allows attackers to execute arbitrary code via uploading a crafted .phar file.

Vulnerability class: Unrestricted File Upload

Published 2026-09-04 · last modified 2026-09-09.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (45.0th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 45th percentile — 45.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.000

Weakness classification (CWE)

CWE-434 — Unrestricted Upload of File with Dangerous Type

Public proof-of-concept exploits

nabeelmkhan/CVE-2026-78839

References

Frequently asked questions

What is CVE-2026-78839?: CVE-2026-78839 is a high-severity vulnerability in N/a, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 8.1/10. Published 2026-09-04.
How severe is CVE-2026-78839?: High severity. CVSS v3 base score is 8.1 out of 10.
Is CVE-2026-78839 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.