Mothra would respect a default value given by a website for HTML file upload forms.

published 2026-05-22 5 mo ago modified 2026-07-23 3 mo ago also EUVD-2026-31401

cvss: 6.9; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits: 0; none known

Mothra would respect a default value given by a website for HTML file upload forms. An attacker could craft a website with a malicious default file path, and then conceal this form element.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 5 mo ago (2026-05-22)

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.9	CVSS: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/AU:N/R:A/RE:L/U:Amber
CNA	4.0	6.9	CVSS: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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:N/R:A/V:X/RE:L/U:Amber

Affected products

9front 9front

Classification

Weakness

CWE-434 Unrestricted Upload of File with Dangerous Type

References

git.9front.org /plan9front/9front/d145acc9ef0da47131af6ad94e87264e04870d47/commit.html
mitigation

Sources

CVE List CVE-2026-9053
NVD CVE-2026-9053

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary