CVE-2026-107586 Allocation of Resources Without Limits or Throttling in hMailServer

Uncontrolled eviction in the browser session table of the REST API in Progressive Robot hMailServer 6.2.28 through 6.3.5 allows a remote authenticated user to end other users' sessions. The table of browser sessions, shared by every account, the server administrator and support sessions, dropped...

EUVD-2026-95038

Uncontrolled eviction in the browser session table of the REST API in Progressive Robot hMailServer 6.2.28 through 6.3.5 allows a remote authenticated user to end other users' sessions. The table of browser sessions, shared by every account, the server administrator and support sessions, dropped...

CVE-2026-107585

Progressive Robot hMailServer versions 6.3.4 and 6.3.5 are vulnerable to an uncontrolled eviction issue in the REST API pending sign-in tables. Because the routes for single sign-on (OpenID Connect, SAML) and passkey challenges are accessible without authentication, an unauthenticated remote atta...

EUVD-2026-95037

Uncontrolled eviction in the pending sign-in tables of the REST API in Progressive Robot hMailServer 6.3.4 and 6.3.5 allows a remote unauthenticated attacker to make other users' OpenID Connect, SAML and passkey sign-ins fail. The routes that start a single sign-on and hand out a passkey sign-in...

CVE-2026-107582

Inefficient algorithmic complexity in the REST API 6.3.3 through 6.3.5 and the IMAP PREVIEW response 6.2.22 through 6.3.5 of Progressive Robot hMailServer allows a remote unauthenticated attacker to make the webmail, the administration console and the REST API unavailable by sending a message. To...

CVE-2026-107580

Inefficient algorithmic complexity in the decoding of message header fields in Progressive Robot hMailServer 6.0.0 through 6.3.5 allows a remote unauthenticated attacker to make the IMAP, SMTP and POP3 services, or the webmail, unavailable by sending a message. The server unfolded a decoded heade...

CVE-2026-107583

Inefficient algorithmic complexity in the webmail's message view of the REST API in Progressive Robot hMailServer 6.3.2 through 6.3.5 allows a remote unauthenticated attacker to make the webmail, the administration console and the REST API unavailable by sending a message. The route that renders ...

CVE-2026-107576

Inefficient algorithmic complexity in the inbound DKIM and ARC signature verification of Progressive Robot hMailServer 6.0.0 through 6.3.5 allows a remote unauthenticated attacker to make the mail services unavailable by sending a message. Building the canonical header and choosing the header...

CVE-2026-107577

Inefficient algorithmic complexity and a non-terminating loop in the MIME processing of received messages in Progressive Robot hMailServer 6.0.0 through 6.3.5 allow a remote unauthenticated attacker to make the mail services unavailable by sending a message. Removing a MIME header parameter whose...

CVE-2026-107574

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...

CVE-2026-107584

Progressive Robot hMailServer versions 6.0.0 through 6.3.5 are vulnerable to a fail-open condition when applying DANE (RFC 7672) to outbound SMTP delivery. The root cause is that the server's validating DNSSEC resolver treats incomplete lookups (no answer, SERVFAIL, or malformed replies), records...

EUVD-2026-94867

Progressive Robot hMailServer 6.0.0 through 6.3.5 fails open when applying DANE RFC 7672 to outbound SMTP delivery. The server's validating DNSSEC resolver treated a TLSA or MX lookup that did not complete no answer, SERVFAIL, a malformed reply, an answer without the requested records and without...

CVE-2026-107583

Progressive Robot hMailServer versions 6.3.2 through 6.3.5 are vulnerable to an inefficient algorithmic complexity flaw in the webmail's message view of the REST API . A remote unauthenticated attacker can send a message containing an HTML reference to a single small embedded image a very large n...

EUVD-2026-94866

Inefficient algorithmic complexity in the webmail's message view of the REST API in Progressive Robot hMailServer 6.3.2 through 6.3.5 allows a remote unauthenticated attacker to make the webmail, the administration console and the REST API unavailable by sending a message. The route that renders ...

CVE-2026-107587

Progressive Robot hMailServer versions 6.3.2 through 6.3.5 are vulnerable to improper certificate validation within the webmail component. A remote unauthenticated attacker can cause the system to retain a signer's certificate—regardless of whether the certificate chain is trusted—under the first...

EUVD-2026-94865

Improper certificate validation in the webmail of Progressive Robot hMailServer 6.3.2 through 6.3.5 allows a remote unauthenticated attacker to have S/MIME-encrypted mail that the account later sends to another correspondent also encrypted to the attacker's key. When its recipient opened a signed...

CVE-2026-107582

Progressive Robot hMailServer versions 6.3.3 through 6.3.5 (REST API) and 6.2.22 through 6.3.5 (IMAP PREVIEW) are vulnerable to an inefficient algorithmic complexity flaw. The issue resides in the server's shared string class , where the replace and remove operations run in quadratic time . A rem...

EUVD-2026-94864

Inefficient algorithmic complexity in the REST API 6.3.3 through 6.3.5 and the IMAP PREVIEW response 6.2.22 through 6.3.5 of Progressive Robot hMailServer allows a remote unauthenticated attacker to make the webmail, the administration console and the REST API unavailable by sending a message. To...

CVE-2026-107580

Progressive Robot hMailServer versions 6.0.0 through 6.3.5 are vulnerable to a Denial of Service (DoS) attack due to inefficient algorithmic complexity during the decoding of message header fields. A remote unauthenticated attacker can send a message containing an RFC 2047 encoded word with a hig...

CVE-2026-107579 Inefficient Algorithmic Complexity in hMailServer

Inefficient algorithmic complexity in the bounce and complaint processing of Progressive Robot hMailServer 6.3.4 and 6.3.5 allows a remote unauthenticated attacker to stop mail delivery by sending messages, when bounce processing or complaint processing is enabled or a mailing list is managed by...