# CVE-2026-17566

## Summary

- **CVE ID:** CVE-2026-17566
- **Severity:** CRITICAL
- **CVSS Score:** 9.9 (CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H)
- **CWE:** CWE-78, CWE-115
- **Published:** Jul 31, 2026
- **Last Modified:** Aug 1, 2026

## Description

pgAdmin 4's Import/Export Data tool builds a psql \copy (...) command line by interpolating a user-supplied SQL query into a Jinja template and passing the rendered line to psql via --command. To stop an attacker from breaking out of the (...) wrapper, create_import_export_job() (route POST /import_export/job/<sid>, gated only by the ordinary, commonly-granted tools_import_export_data permission) validated the query with a hand-written parenthesis-balance checker, _is_query_parens_balanced(). That checker always treated a backslash before a single quote (\') as escaping the quote, i.e. as if standard_conforming_strings were off. PostgreSQL has defaulted standard_conforming_strings to on since 9.1 (2010), the default on every PostgreSQL version pgAdmin 4 currently supports (13-18); under that default psql's own \copy tokenizer treats \ as an ordinary character, so a single quote immediately after it closes the string literal. A query such as SELECT 'a\') TO PROGRAM 'echo pwned' x' was therefore accepted as "balanced" by pgAdmin's checker (which believed the ) was still inside the string), while psql, run through the actual rendered command line, closes the string at that point and treats the following ) as the end of the wrapping \copy (...) subquery, exposing an attacker-chosen TO PROGRAM '<command>' clause that psql executes via popen() -- independent of a subsequent syntax error later on the same line. This is the same class of bug as CVE-2025-12762/CVE-2025-13780 (RCE via psql meta-command/COPY injection during PLAIN-format dump restore), reached through an independently written defense in a different module (Import/Export Data rather than Restore) that had its own, different logic bug (inverted backslash-escape semantics rather than a BOM-defeated regex anchor).

The fix rejects any backslash inside a single-quoted string in the query outright, rather than picking one of the two possible psql interpretations. This is intentionally conservative: because the correct interpretation of \ depends on the target server's standard_conforming_strings setting, which the checker cannot reliably know at validation time, refusing the query is safer than guessing.

This issue affects pgAdmin 4: from the introduction of _is_query_parens_balanced() before 9.18.

## Affected Products

- pgadmin.org — pgAdmin 4 (0)

## References

- [CNA](https://github.com/pgadmin-org/pgadmin4/issues/10213)
- [CNA](https://github.com/pgadmin-org/pgadmin4/commit/1496fabe28c9f825f6bac0f0d000d9d3276322c3)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.49%
- **EPSS Percentile:** 40.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._