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VulnerabilityPublished Updated

CVE-2026-58399: antonio-castellon module-auth · Improper Authentication

Affects antonio-castellon module-authSource CVE Database V5

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Not known to be exploited · CVSS 8.7 High : upgrade to 2.3.0 soon.

Data as of 13 Nov 2026, 23:54 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.9% chance of exploitation in 30 days – higher than 62% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.3.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

What to do

Upgrade module-auth and @acastellon/auth to 2.3.0.

Affected software

ProductAffectedFixed in
antonio-castellonmodule-authAffected
  • <2.3.0
Fixed in
  • 2.3.0
npm@acastellon/authpkg:npm/@acastellon/authOther threatsAffected
  • <2.3.0
Fixed in
  • 2.3.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to version 2.3.0 or later, where the authentication bypass vulnerability has been fixed. No other official remediation or temporary fixes are indicated. Patch status is confirmed by the vendor's versioning information.

Description

@acastellon/auth is an authentication control system for microservices. Versions prior to 2.3.0 appear to allow an unauthenticated authentication bypass in validateToken() through spoofable auth-user and Host request headers. The validateToken middleware contains a service-to-service bypass for auth-user: service-brother when req.get('host').startsWith(getHostName()). Both values involved in the check can be influenced by an unauthenticated HTTP client: auth-user is a request header, and Host is also client-controlled. As a result, a remote unauthenticated attacker can send a request with crafted headers and bypass token validation before the normal legacy/JWT/OIDC validation logic runs. A fix has been implemented in v2.3.0.

References

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