{"id":"CVE-2026-17351","summary":"pgAdmin 4: AI Assistant read-only transaction bypass via sqlparse/PostgreSQL lexer disagreement (incomplete fix for CVE-2026-12045)","details":"The fix for CVE-2026-12045 in pgAdmin 4 9.16 required the LLM-supplied query passed to the AI Assistant's execute_sql_query tool to parse, via sqlparse, as exactly one non-transaction-control statement before running it inside a BEGIN TRANSACTION READ ONLY wrapper. sqlparse's string-literal lexing can disagree with PostgreSQL's own parser: under standard_conforming_strings = on (PostgreSQL's default since 9.1), a backslash immediately before a quote is an ordinary character to PostgreSQL, but sqlparse treats it as escaping the quote. A payload such as SELECT '\\';COMMIT;CREATE TABLE pwn(x int);SELECT 1 --' therefore parses as a single SELECT to sqlparse's validator, while PostgreSQL executes it as four statements: the smuggled COMMIT ends the wrapping read-only transaction, and the trailing ROLLBACK becomes a no-op. This reintroduces the same write/RCE bypass CVE-2026-12045 was meant to close, reachable via the same indirect prompt-injection delivery (an attacker plants the payload in any object the AI Assistant may read; the LLM emits it as a tool call).\n\nAn initial candidate fix ran the query with psycopg's execute(..., prepare=True), intending to force PostgreSQL's own Parse step (extended query protocol) to reject multi-statement text regardless of sqlparse's classification. This candidate fix does not work as submitted: psycopg3's PrepareManager silently ignores the prepare argument whenever the connection's prepare_threshold is None, which is pgAdmin's default for every server connection (the per-server \"Prepare threshold\" field is blank unless an administrator explicitly sets it) -- psycopg3 falls back to the simple query protocol, the same multi-statement-capable path the bypass exploits, so the candidate fix closes nothing on any real-world default configuration.\n\nThe corrected fix sets conn.prepare_threshold = 0 directly on the dedicated, single-use read-only connection the AI Assistant tool opens, structurally forcing the extended query protocol independent of any server-level configuration. Verified against a live PostgreSQL 18 instance: the payload executes successfully under the prepare_threshold=None (default) behavior, and is rejected with \"cannot insert multiple commands into a prepared statement\" once prepare_threshold=0 is set on that connection.\n\nThis issue affects pgAdmin 4: from 9.13 before 9.17.","modified":"2026-08-14T10:42:13.197717425Z","published":"2026-07-31T16:00:19.103Z","related":["openSUSE-SU-2026:11508-1"],"database_specific":{"cwe_ids":["CWE-115","CWE-89"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/17xxx/CVE-2026-17351.json","cna_assigner":"PostgreSQL"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/17xxx/CVE-2026-17351.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-17351"},{"type":"REPORT","url":"https://github.com/pgadmin-org/pgadmin4/issues/10192"},{"type":"FIX","url":"https://github.com/pgadmin-org/pgadmin4/commit/bf4792444446f0e7ab721d23cbd6bfe6afaa7a8b"},{"type":"FIX","url":"https://github.com/pgadmin-org/pgadmin4/commit/ef76102bcd1cdb544eb9b4ef18d3382f22b76752"},{"type":"PACKAGE","url":"https://github.com/pgadmin-org/pgadmin4"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/pgadmin-org/pgadmin4","events":[{"introduced":"5b231ddd3f7aca5d6e7c03c21e7e1bc94b8c3b03"},{"fixed":"067f7af2274cf034623426d2b74a7695018a5f1f"},{"fixed":"bf4792444446f0e7ab721d23cbd6bfe6afaa7a8b"},{"fixed":"ef76102bcd1cdb544eb9b4ef18d3382f22b76752"}],"database_specific":{"source":["CPE_RANGE","REFERENCES"],"cpe":"cpe:2.3:a:pgadmin:pgadmin_4:*:*:*:*:*:postgresql:*:*","extracted_events":[{"introduced":"9.13"},{"fixed":"9.17"}]}}],"versions":["REL-9_16","REL-9_15","REL-9_14","REL-9_13"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-17351.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H"}]}