High File handling

CVE-2026-46400 — HAXCMS PHP has a File Upload Validation Bypass

HAX CMS helps manage microsite universe with PHP or NodeJs backends. Starting in version 11.0.6 and prior to version 25.0.0, the file upload functionality in HAXCMS PHP only validates file extensions using a regex pattern without checking the actual file content or MIME type. This allows attackers to upload malicious files (e.g., PHP webshells) disguised as legitimate image files, potentially leading to remote code execution. Version 25.0.0 contains a fix for the issue.

Published Jun 5, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.6% (30-day exploitation probability)+7
Technical severity (high)+6
CISA SSVC: exploitation "poc"+5

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.6%

ahead of 47% of scored CVEs · Oct 14, 2026

Affects

Haxtheweb

Haxcms-php

CVSS base

8.7

High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

Proof of concept

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Haxtheweb Haxcms-php).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (file handling), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Haxtheweb	Haxcms-php	version >= 11.0.6, < 25.0.0	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

Low

User interaction

None

Scope

Confidentiality (vulnerable system)

High

Integrity (vulnerable system)

High

Availability (vulnerable system)

High

Confidentiality (subsequent)

None

Integrity (subsequent)

None

Availability (subsequent)

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
8.7	CVSS 4.0	High	—	—	security-advisories@github.com via NIST National Vulnerability Database
8.7	CVSS 4.0	High	—	—	GitHub_M via CVE Program (cve.org) e CISA ADP

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/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:X/R:X/V:X/RE:X/U:X

(score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-434 · Unrestricted Upload of File with Dangerous Type

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.60%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Monitor file creation in web directories and paths with traversal sequences (../).

web/proxy/WAF logsnetwork IDS/IPSfile integrity (FIM)endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

2026
Affected products added · haxtheweb/haxcms-php
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 8.7
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Deferred
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Jun 5, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

github.com/haxtheweb/issues/security/advisories/GHSA-ffxv-9qv2-v2v8
x_refsource_CONFIRM, NIST National Vulnerability Database

Elsewhere on this site

Haxtheweb
every CVE for this vendor

File handling
same class

CWE-434
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-46493 haxtheweb/haxcms-php uses insecure method for generating salt Jun 5, 2026
High CVE-2026-46398 HAX CMS Missing Secure Flag on Cookie Jun 5, 2026
Medium CVE-2026-46397 haxcms-php Local File Inclusion via saveOutline API Location Parameter v2.0 Jun 5, 2026
High CVE-2026-46511 HAXcms: Mass Token Exfiltration and Cross-Tenant Hijack Jun 5, 2026
High CVE-2026-46392 HAX CMS PHP Has a Stored XSS via Case-Sensitivity Mismatch in HTML Upload Validation Jun 5, 2026
High CVE-2026-46394 HAX CMS Vulnerable to Command Injection using Git.php Jun 5, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-46400 is "HAXCMS PHP has a File Upload Validation Bypass", rated High. It affects Haxcms-php (Haxtheweb); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.7 describes technical severity. EPSS 0.60% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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