Vulnerabilidad · Publicado 08/10/2026
Una deficiencia en el lector JSON de hMailServer permite a atacantes remotos no autenticados causar indisponibilidad de servicios de correo mediante objetos JSON malformados con miembros duplicados. El procesamiento O(N²) genera degradación severa: 1 MB consume 8.9 segundos y 4 MB alcanza 300 segundos. Afecta empresas y proveedores de correo en LATAM que implementen este servidor de mensajería.
Inefficient algorithmic complexity in the JSON reader of Progressive Robot hMailServer allows a remote unauthenticated attacker to make the mail services unavailable. Reading a JSON object kept the first of each duplicated member name by searching the members already read, so an object of N distinct member names cost O(N^2): 1 MB took 8.9 seconds and 4 MB took 300 seconds against the affected code. A remote attacker reaches the reader without an account by mailing a crafted TLS-RPT report (up to 16 MB after decompression) to a hosted domain's published report mailbox, which is read on a delivery thread; a few such reports hold every delivery thread (ten by default), so the server delivers no mail, local or outbound, for over an hour per report. A signed-in account reaches the same 16 MB body through the webmail's own REST routes, holding the REST API's own worker threads. Where no report mailbox is configured, the unauthenticated REST sign-in routes that read a JSON body are capped at 64 KB and are not affected.
Score: 7.5/10 — Severidad: HIGH — Estado NIST: Received
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-407
Publicado en NIST NVD.