Portal del Hermano (portaldelhermano.es): Improper Restriction of Excessive Authentication Attempts
CVE-2026-53997 is a high-severity improper restriction of excessive authentication attempts vulnerability in Portal del Hermano (portaldelhermano.es) from NetHerman, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 2026-10-06 as the first without the flaw, so updating Portal del Hermano (portaldelhermano.es) to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.4% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Portal del Hermano (portaldelhermano.es) to 2026-10-06 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| NetHerman | Portal del Hermano (portaldelhermano.es) | before 2026-10-06 | 2026-10-06 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.1 | Critical | CNA (vulncheck.com) |
| CVSS 3.1 | 7.4 | High | CNA (vulncheck.com) |
Official description
Netherman Portal del Hermano (portaldelhermano.es) before 2026-10-06 contains a broken authentication vulnerability in its password-recovery flow at the POST /password/create-access and POST /password/email endpoints, allowing unauthenticated attackers to take over any member account across all tenants by exploiting the lack of rate limiting and distinct error messages that act as oracles for each of the four identity-verification factors (DNI, date of birth, phone number, last four IBAN digits). Attackers can confirm the DNI via the oracle, brute-force the date of birth and IBAN digits, obtain the phone number through open-source intelligence, then submit an attacker-controlled email field so the password reset link is delivered to them, enabling full account takeover including profile data, full IBAN, and fiscal documents.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of Excessive Authentication Attempts
The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame.
How developers prevent this class of flaw
- Common protection mechanisms include: Disconnecting the user after a small number of failed attempts Implementing a timeout Locking out a targeted account Requiring a computational task on the user's part.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.
More Improper Restriction of Excessive Authentication Attempts vulnerabilities (CWE-307)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Recent Improper Restriction of Excessive Authentication Attempts vulnerabilities
- 9.1 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 7.4 High severity
- 9.1 Critical severity
- 7.5 High severity
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