CVE-2026-46395
HAX CMS Vulnerable to Private Key Disclosure via Broken HMAC Implementation
Description
HAX CMS helps manage microsite universe with PHP or NodeJs backends. Prior to version 26.0.0, the `hmacBase64()` function in the HAXcms Node.js backend contains two critical cryptographic implementation errors that together allow any unauthenticated attacker to extract the system’s private signing key and forge arbitrary admin-level JSON Web Tokens (JWTs) allowing them to get full admin access with a single HTTP request. First, the function passes the literal string "0" as the HMAC signing key instead of the key parameter, making every HAXcms instance compute identical HMACs for the same input. Then, after computing the HMAC, the function concatenates the real key parameter which is "this.privateKey + this.salt", the system’s master signing secret is directly onto the output. The combined buffer is base64-encoded and returned as the token. Every base64url token produced has the same structure: 32 bytes HMAC keyed with "0" and N bytes of `privateKey+salt`. An attacker base64-decodes any token, discards the first 32 bytes, and reads the private key directly. The `/system/api/connectionSettings` endpoint is unauthenticated and returns multiple tokens generated by this function. A single GET request to this endpoint exposes the private key. The PHP backend implements this function correctly with the actual key and returns only the hash. The PHP version produces 44-character tokens whereas the broken Node.js version produces 139+ character tokens. Version 26.0.0 fixes the issue.
INFO
Published Date :
June 5, 2026, 7:16 p.m.
Last Modified :
June 5, 2026, 7:20 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | CRITICAL | [email protected] |
Solution
- Update HAXcms Node.js backend to version 26.0.0 or later.
- Verify the fixed HMAC function implementation.
- Remove any exposed private signing keys.
- Invalidate and re-issue all existing tokens.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-46395.
| URL | Resource |
|---|---|
| https://github.com/haxtheweb/issues/security/advisories/GHSA-6c8g-9hfh-pq5h |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-46395 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-46395
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-46395 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-46395 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Jun. 05, 2026
Action Type Old Value New Value Added Description HAX CMS helps manage microsite universe with PHP or NodeJs backends. Prior to version 26.0.0, the `hmacBase64()` function in the HAXcms Node.js backend contains two critical cryptographic implementation errors that together allow any unauthenticated attacker to extract the system’s private signing key and forge arbitrary admin-level JSON Web Tokens (JWTs) allowing them to get full admin access with a single HTTP request. First, the function passes the literal string "0" as the HMAC signing key instead of the key parameter, making every HAXcms instance compute identical HMACs for the same input. Then, after computing the HMAC, the function concatenates the real key parameter which is "this.privateKey + this.salt", the system’s master signing secret is directly onto the output. The combined buffer is base64-encoded and returned as the token. Every base64url token produced has the same structure: 32 bytes HMAC keyed with "0" and N bytes of `privateKey+salt`. An attacker base64-decodes any token, discards the first 32 bytes, and reads the private key directly. The `/system/api/connectionSettings` endpoint is unauthenticated and returns multiple tokens generated by this function. A single GET request to this endpoint exposes the private key. The PHP backend implements this function correctly with the actual key and returns only the hash. The PHP version produces 44-character tokens whereas the broken Node.js version produces 139+ character tokens. Version 26.0.0 fixes the issue. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/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 Added CWE CWE-200 Added CWE CWE-327 Added CWE CWE-321 Added Reference https://github.com/haxtheweb/issues/security/advisories/GHSA-6c8g-9hfh-pq5h