CVE-2026-58225
LowCVSS 2.1Summary
SQL Injection vulnerability in the postgrex library for Elixir allows an attacker to inject SQL via a LISTEN channel name. The issue occurs during reconnection when channel names are concatenated in an anonymous code block, and the quote_channel/1 function does not escape the $$ delimiter, causing the notification connection to break and resulting in denial of service.
Risk Assessment
An attacker can permanently break the notification connection for all tenants sharing the same connection, leading to loss of notifications and denial of service. The vulnerability affects systems that pass untrusted input (e.g., user identifiers) as channel names.
Recommendation
Immediately update the postgrex library to version 0.22.3 or later. If an update is not possible, avoid passing untrusted data as channel names to the listen/3 function.
Original NVD description (English source)
SQL Injection vulnerability in elixir-ecto postgrex allows an attacker who can influence a LISTEN channel name to inject SQL into the reconnect replay query, causing a denial of service of the notification connection. Postgrex.Notifications sanitizes channel names with quote_channel/1, which doubles double quotes so the name is safe inside a double-quoted identifier. This protects the single-statement LISTEN and UNLISTEN paths. On every (re)connect, however, handle_connect/1 replays all registered channels at once by concatenating their LISTEN statements and wrapping them in a dollar-quoted anonymous code block (DO $$BEGIN ... END$$). quote_channel/1 does not escape the $$ dollar-quote delimiter that opens and closes this block. The listen/3 guards only reject null bytes and names longer than 63 bytes, so a channel name containing $$ passes validation unchanged. Once such a name is embedded, its $$ prematurely terminates the outer dollar-quoted string and PostgreSQL parses the remainder as additional top-level statements. Because handle_connect/1 runs on every (re)connect, the malformed replay query is rejected each time and the notification connection never re-establishes its subscriptions, silently dropping notifications for every channel sharing that connection. An application is affected when it passes untrusted input (for example a tenant or user identifier) as a channel name to Postgrex.Notifications.listen/3. The double-quote doubling prevents forming a fully valid injected statement, so arbitrary SQL execution is not possible, but the corrupted query reliably breaks the shared notification connection for all tenants, resulting in denial of service. This issue affects postgrex: from 0.16.0 before 0.22.3.