CVE-2026-75513

CRITICAL CVSS 9.1 PoC Available
Published: 2026-09-16
Modified: 2026-09-16
Enriched via mock
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AI Threat Summary

CVE-2026-75513 is a critical vulnerability with a CVSS score of 9.1 affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.

Description

Marten is a .NET Transactional Document DB and Event Store on PostgreSQL. From version 7.0.0 until 9.13.0, several Marten LINQ and tenant-management paths interpolate runtime, potentially attacker-controlled strings into single-quoted SQL literals without escaping or parameterization. The primary confirmed vector is a dictionary indexer key used by Where filters in src/Marten/Linq/Members/Dictionaries/DictionaryItemMember.cs. Additional affected sinks include SelectParser.cs, DatabaseScopedTenantPartitions.cs, and DeleteAllForTenant.cs reached through IEventStore.DeleteProjectionProgressAsync, while DictionaryContainsKeyFilter.cs (Newtonsoft serializer only; System.Text.Json is not affected) handles ContainsKey calls. Events/Daemon/Internals/EventLoader.cs contains a related per-tenant partition-pruning literal that the advisory identifies as a defense-in-depth sink. A crafted single quote can escape the generated literal, enabling filter or multi-tenant authorization bypass and blind data exfiltration, and deployments that permit semicolon-batched Npgsql statements may also allow data modification. This issue is fixed in version 9.13.0.

Attack Chain
1
Reconnaissance

Attacker scans for vulnerable versions using version banners or PoC scanners

2
Initial Access

Attacker triggers CVE-2026-75513 vulnerability with a crafted request or payload

3
Execution

Vulnerability exploited to perform unauthorized actions on the target system

4
Impact

Depending on vulnerability type, attacker achieves data access, service disruption, or code execution

MITRE ATT&CK Techniques
T1190 Exploit Public-Facing Application
Initial Access

Public-facing application vulnerability exploited for initial access

T1203 Exploitation for Client Execution
Execution

Vulnerability exploited to execute attacker-controlled code

Indicators of Compromise
Type Value Description
user_agent Mozilla/5.0 (compatible; exploit/1.0) Generic exploit scanner user agent pattern
url /api/vuln-endpoint?payload=<malicious> Exploit attempt against application endpoint — monitor access logs for anomalous params
Remediation
1. Apply vendor-supplied security patches immediately. 2. If patches are unavailable, apply recommended mitigations from the vendor advisory. 3. Enable WAF rules or IDS signatures to detect exploitation attempts. 4. Monitor logs for indicators of compromise listed above. 5. Implement network segmentation to limit blast radius if exploitation occurs. 6. Subscribe to vendor security advisories for this product.
Quick Facts
CVE ID CVE-2026-75513
CVSS Score 9.1
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
Published 2026-09-16
Exploited No
CISA KEV No
PoC Available
References
External Resources
NVD Entry BleepingComputer The Hacker News