Marten's LINQ provider has SQL injection via unescaped string literals

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.1 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L

EPSS

• CVE-2026-75513: 0.47% estimated exploitation activity in the next 30 days; percentile 40.54 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Several code paths in Marten's LINQ provider and tenant-management internals interpolated a runtime, potentially attacker-influenced value into generated SQL as a single-quoted string literal without escaping or parameterization. A value containing a single quote (') could break out of the literal and inject arbitrary SQL. The primary vector is a Dictionary<, indexer key used in a Where filter — Where(x = x.Attributes[key] == v) — a common "filter by attribute name" / EAV pattern. It is confirmed with an executed proof-of-concept and yields filter / multi-tenant authorization bypass (returning other tenants' rows) and blind data exfiltration. Where the application permits ;-batched statements (Npgsql default), data modification is also possible. Affected sinks - Linq/Members/Dictionaries/DictionaryItemMember.cs — dictionary indexer key (primary, confirmed PoC) - Linq/Members/Dictionaries/DictionaryContainsKeyFilter.cs — Dictionary.ContainsKey(key) (Newtonsoft serializer only;…

Published by the source

17 Sep 2026, 14:51 UTC

Last modified by the source

17 Sep 2026, 15:00 UTC

Source last checked

26 Oct 2026, 17:05 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-rfx3-98h7-v3xp

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-rfx3-98h7-v3xp

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-75513

Advisory: Marten's LINQ provider has SQL injection via unescaped string literals
IDs: CVE-2026-75513, GHSA-rfx3-98h7-v3xp
Record: https://patchnext.com/advisories/cve-2026-75513 (revision 2, source checked 26 Oct 2026, 17:05 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: marten 9.13.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet marten: affected >= 7.0.0, <= 9.12.0; fixed in 9.13.0

## Suggested inspection (read-only)
- NuGet marten: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on marten.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-rfx3-98h7-v3xp (OSV record GHSA-rfx3-98h7-v3xp lists affected ranges: NuGet marten >=7.0.0 <9.13.0 (fixed))
- Verified: https://github.com/advisories/GHSA-rfx3-98h7-v3xp (GitHub-reviewed advisory GHSA-rfx3-98h7-v3xp lists affected ranges: NuGet marten >=7.0.0 <=9.12.0)

Commands are suggestions: review each one before running it.