CVE-2026-45288

Marten's full-text search APIs interpolated the user-supplied regConfig parameter directly into the generated SQL without parameterization or validation, making every code path that exposes regConfig to untrusted input a SQL injection sink.

Affected APIs

• IQuerySession.SearchAsync<T>(string searchTerm, string regConfig, ...)
• IQuerySession.PlainTextSearchAsync<T>(...)
• IQuerySession.PhraseSearchAsync<T>(...)
• IQuerySession.WebStyleSearchAsync<T>(...)
• IQuerySession.PrefixSearchAsync<T>(...)
• IQueryable<T>.Where(x => x.Search(term, regConfig)) and the matching PlainTextSearch / PhraseSearch / WebStyleSearch / PrefixSearch extension methods

Details

In the affected versions, FullTextWhereFragment renders the WHERE-clause SQL by string interpolation:

private string Sql =>
    $"to_tsvector('{_regConfig}'::regconfig, {_dataConfig}) @@ {_searchFunction}('{_regConfig}'::regconfig, ?)";

_regConfig arrives unchanged from the public API surface above. Any value containing a single quote terminates the SQL literal and lets an attacker append arbitrary PostgreSQL.

Confirmed exploit shapes (with regConfig set to attacker-controlled input)

All five overloads listed above produced SQL containing the verbatim payload.

Workarounds

If users cannot upgrade immediately, do one of the following at the application boundary:

1. Hard-code regConfig to a compile-time constant ("english", "simple", …) and never accept it from request input.
2. Validate any externally-sourced regConfig value before passing it to Marten, e.g. against the same regex as the patch (^[a-zA-Z_][a-zA-Z0-9_]*(\.[a-zA-Z_][a-zA-Z0-9_]*)?$) or against an allowlist of PostgreSQL configurations the application actually uses.
3. Drop the regConfig argument from the call site so Marten falls back to the safe default.

Resources

• Patch PR: JasperFx/marten#4343
• Patched file: FullTextWhereFragment.cs
• Regression tests: full_text_regconfig_sql_injection.cs
• CWE-89: https://cwe.mitre.org/data/definitions/89.html

Credit

Reported privately to the JasperFx team with a working proof of concept covering all five affected overloads.

• Confidentiality: an attacker can append arbitrary SELECT statements and exfiltrate database contents through error channels, response timing, or, if the application surfaces query results, directly.
• Integrity / Availability: DDL, UPDATE, DELETE, and pg_sleep-style denial-of-service payloads succeed under the same vector. Concrete impact depends on the database role used by the Marten connection string.
• Precondition: the calling application must forward attacker-controlled input into the regConfig parameter (e.g. a ?lang= query string mapped to regConfig). Applications that hard-code regConfig to a compile-time constant are not exploitable.

Untrusted input alters a database query, allowing the attacker to read or modify data the query was not intended to access. Typical impact: data disclosure or modification.

CVE-2026-45288 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (8.37.0); upgrading removes the vulnerable code path.

Kodem intelligence

Fixed in Marten 8.36.1 (and forward) by #4343.

FullTextWhereFragment now validates regConfig against ^[a-zA-Z_][a-zA-Z0-9_]*(\.[a-zA-Z_][a-zA-Z0-9_]*)?$ (a simple PostgreSQL identifier, optionally schema-qualified, capped at NAMEDATALEN-1 per side) and throws ArgumentException for anything else. The default value ("english"), schema-qualified configs ("pg_catalog.english"), and the standard PostgreSQL text-search configurations all continue to work.

1. What is CVE-2026-45288? CVE-2026-45288 is a critical-severity SQL injection vulnerability in Marten (nuget), affecting versions <= 8.36. It is fixed in 8.37.0. Untrusted input alters a database query, allowing the attacker to read or modify data the query was not intended to access.
2. How severe is CVE-2026-45288? CVE-2026-45288 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of Marten are affected by CVE-2026-45288? Marten (nuget) versions <= 8.36 is affected.
4. Is there a fix for CVE-2026-45288? Yes. CVE-2026-45288 is fixed in 8.37.0. Upgrade to this version or later.
5. Is CVE-2026-45288 exploitable, and should I be worried? Whether CVE-2026-45288 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-45288 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-45288? Upgrade Marten to 8.37.0 or later.