Misinterpretation of Input in hMailServer

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-126619
StatePUBLISHED
AssignerGitLab
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-11 09:17:14 UTC
Updated2026-11-11 09:17:14 UTC
DescriptionMisinterpretation of SQL statement text in the database layer of Progressive Robot hMailServer 6.0.0-B1 through 6.3.7 allows a remote unauthenticated attacker to have a failed database write reported to the server as successful. The layer answers a failed statement as a success when it finds the marker [IGNORE-ERRORS], which is meant only for the server's own schema statements (its upgrade scripts and the database log's tables), and statements carry values from outside - an envelope address, the user name of a failed logon, a message's headers - in their text on MySQL/MariaDB and PostgreSQL, and in the batches of the database log on every engine. Up to 6.2.18 the marker was honoured anywhere in a statement, a value included, on MySQL/MariaDB and PostgreSQL. From 6.2.19 it was honoured only inside a comment, but the layer read a backslash inside a string literal as an escape, which SQL Server, SQL Server Compact and PostgreSQL with standard_conforming_strings on (its default) do not, so that on those engines a value holding a backslash could make the layer take part of the statement's literals for statement text and find the marker there: on PostgreSQL from 6.3.3 for every statement carrying an outside value that holds a backslash, with no setting changed for a message delivered into a local mailbox (through an internationalised (SMTPUTF8) envelope sender) and for the IP range an auto-ban writes (named after the user name of the failed logon), and on SQL Server and SQL Server Compact for the database log, when the server logs to the database (logging is off, and the log device is files, by default). A statement run outside a transaction that then failed - a constraint, a deadlock, a lock or statement timeout, a full disk, and up to 6.2.18 a lost connection - was answered as a success, and its caller went on as if the row had been written: a message delivered into a local mailbox could be counted as delivered with no row to show it and no failure notice to its sender, and a message accepted with 250 could be left with no queue row and never delivered (up to 6.2.18, and on PostgreSQL from 6.3.3 when every recipient's address carries the marker too, which needs an address that takes any local part); an auto-ban whose IP range was not written could be logged and counted as applied, with no error reported, while the address stayed unbanned; and message metadata (written only when message indexing is on), entries of the database log and rows of features an administrator turns on could be lost without an error. On MySQL/MariaDB up to 6.2.18 the caller was handed whatever identifier the client library still held for the connection - 0, or that of an insert its last successful statement made, in whatever table - under which a queued message's recipients were then written, so that another message still in the queue could be delivered to them as well. This flaw gives a value no way to change what a statement does, and no privilege is gained.

Risk And Classification

Primary CVSS: v3.1 4.8 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Problem Types: CWE-115 | CWE-115 CWE-115: Misinterpretation of Input

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary4.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
3.1CNACVSS4.8MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Progressive Robot Ltd HMailServer affected 6.0.0-B1 6.3.7 semver Not specified

References

ReferenceSourceLinkTags
gitlab.com/hmailserver/hmailserver/-/work_items/100 [email protected] gitlab.com
gitlab.com/hmailserver/hmailserver/-/releases/v6.3.8 [email protected] gitlab.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Found by the hMailServer project (Progressive Robot Ltd) (en)

Additional Advisory Data

Solutions

CNA: Upgrade to hMailServer 6.3.8, which reads each string literal as the database engine reads it - a backslash as an escape only on MySQL/MariaDB, on PostgreSQL with standard_conforming_strings off and in PostgreSQL's E'...' strings - when it looks for the marker, so that no value can reach the comment where the marker is honoured, and which reads literals the same way when it masks them in the slow-query log line and the trace. Until then, on SQL Server and SQL Server Compact keep logging off or the log device on files (the defaults); on PostgreSQL 6.3.3 to 6.3.7, and on MySQL/MariaDB and PostgreSQL before 6.2.19, no setting of the server avoids it.

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