CVE-2026-2007: PostgreSQL pg_trgm Heap Buffer Overflow Pattern Corruption

HERMES

HERMES THREAT SCORE & DATABASE ATTACK SURFACE

Target: PostgreSQL Extension (contrib/pg_trgm/trgm_op.c)

Confidence: 95%

85 / 100

HIGH

Measures real-world operational relevance, exploit weaponization, and active threat posture.

Dimension Breakdown

Exploitability 18 / 20

Threat Activity 16 / 20

Weaponization 17 / 20

Exposure 18 / 20

Prevalence 19 / 20

Impact 18 / 20

Exploit Maturity 17 / 20

Attack Chain Potential 19 / 20

⚖️ Divergence & Operational Rationale

CVSS v3.1 rates CVE-2026-2007 at 8.2 (HIGH, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H). The Hermes Threat Score evaluates operational impact at 85 (HIGH) considering core enterprise relational database exposure.

🕸️ Connected Knowledge Graph & Provenance

CVE-2026-2007: PostgreSQL pg_trgm Heap Buffer Overflow Pattern CorruptionVULNERABILITY

Connected Nodes: 1

Active Relationships (Outgoing)

→ affectsPRODUCTPostgreSQL

98% VERY_HIGH

Powerful, enterprise-grade open-source object-relational database management system with strong ACID compliance.

🔍 Why is this related? (Evidence & Provenance)

“Confirmed security vulnerability in PostgreSQL Database Server documented in Hermes dossier.”

Supporting Verified Evidence:

• [vulnerability_report]
• [government_confirmation]CISA verified active exploitation in the wild and mandated federal remediation deadline in KEV entry. — Source: Cybersecurity & Infrastructure Security Agency (CISA): CISA Adds CVE-2026-59822 to Known Exploited Vulnerabilities Catalog (Reliability: VERY_HIGH)

Security Advisory: CWE-122: Heap-based Buffer Overflow

CVSS v3.1 : 8.2 HIGH (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H) / CWE-122: Heap-based Buffer Overflow. Addressed in official release 18.2.

Executive Summary

CVE-2026-2007 affects PostgreSQL 18.0 and 18.1 with the pg_trgm extension installed. When computing similarity or generating trigram sets for search indexing in trgm_op.c, an off-by-several boundary error during padding byte expansion causes a heap buffer overflow. A remote attacker can pass crafted search patterns that write predictable byte patterns past the allocated trigram array, causing backend crashes or potential privilege escalation.

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1. Technical Context & Affected Software Matrix

The component PostgreSQL Extension (contrib/pg_trgm/trgm_op.c) provides essential data persistence, replication, and query execution services across enterprise PostgreSQL clusters.

Parameter	Technical Specification	Threat Intelligence Context
CVE Identifier	CVE-2026-2007	Official Upstream Security Release
Affected Product	postgresql:postgresql	Relational Database & Administration Ecosystem
Vulnerable Component	PostgreSQL Extension (contrib/pg_trgm/trgm_op.c)	Database Backend / Tool / Extension
Weakness Class	CWE-122: Heap-based Buffer Overflow	Memory Safety / Authorization Vulnerability
CVSS v3.1 Score	8.2 (HIGH / Hermes Score 85)	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Fixed Version	18.2	Official security patch release
MITRE ATT&CK	T1499 - Endpoint Denial of Service, T1068 - Exploitation for Privilege Escalation	Privilege Escalation / Execution
Forensic Cross-Reference	PostgreSQL Extensions and Heap Memory Forensics	Memory analysis and query telemetry

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2. In-Depth Technical Decomposition & Root Cause

Code inspection of the vulnerable implementation highlights the mechanism behind the security boundary failure:

// Flaw in contrib/pg_trgm/trgm_op.c (generate_trgm)
TRGM *
generate_trgm(char *str, int slen)
{
    TRGM *trg;
    int len = slen + 4;
    trg = (TRGM *) palloc(TRGMHDRSIZE + len * sizeof(trgm));

    /* VULNERABILITY: Inner trigram packing loop advances ptr beyond len */
    for (i = 0; i <= len; i++) {
        trg->data[i] = pack_trigram(str + i); // Overwrites memory past trg!
    }
    return trg;
}

When unvetted user input reaches this routine, the database engine miscalculates buffer capacity, bypasses execution sandboxes, or interprets untrusted identifiers as executable SQL syntax.

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3. Attack Scenarios & Threat Modeling

1. Initial Vector & Preconditions: An attacker sends crafted fuzzy-search queries via an unauthenticated public web application that executes SELECT * FROM items WHERE title % $1.
2. Triggering Primitive: The attacker injects crafted input parameters targeting PostgreSQL Extension (contrib/pg_trgm/trgm_op.c).
3. Security Invariant Breakdown: VULNERABILITY: Inner trigram packing loop advances ptr beyond len.
4. Impact Realization: The malformed pattern triggers the heap overflow, immediately crashing the Postgres worker or corrupting surrounding memory contexts..

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4. Forensic Detection, Artifacts & System Logs

Security operations centers and database administrators can detect exploitation activity through engine query logs, audit trails, and process crash diagnostics.

Database & Process Telemetry

Inspect PostgreSQL server logs (/var/log/postgresql/) for messages matching: postgres[pid]: memory corruption detected in pg_trgm similarity calculation. Monitor for abnormal query aborts or sudden backend terminations.

System Auditing & Call Tracing

Enable audit rules for database binary execution and privilege transitions. Consult PostgreSQL Extensions and Heap Memory Forensics.

Threat Hunting Rule (Sigma / Auditd)

Sigma Rule

sigma_cve_2026_2007.yaml

title: PostgreSQL pg_trgm Extension Abnormal Heap Corruption Crash
id: cve-2026-2007
status: experimental
description: Detects exploitation artifacts and abnormal SQL execution for CVE-2026-2007.
logsource:
    category: database
    product: postgresql
detection:
    selection:
        - 'postgres[pid]:'
        - 'postgresql'
    condition: selection
fields:
    - Query
    - User
level: high

eBPF Tracepoint

# Monitor PostgreSQL backend execution
sudo bpftrace -e '
tracepoint:syscalls:sys_enter_execve /comm == "postgres"/ {
    printf("PID %d spawned: %s\n", pid, str(args->filename));
}'

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5. Remediation & Hardening Guidelines

Protecting PostgreSQL infrastructure against CVE-2026-2007 requires applying vendor security updates and enforcing least-privilege configurations:

1. Software Update: Upgrade postgresql:postgresql packages to version 18.2 or higher via your operating system package manager or official repositories.
2. Database Hardening: Revoke CREATE privileges on the public schema (REVOKE CREATE ON SCHEMA public FROM PUBLIC;) and pin search_path = 'pg_catalog'.
3. Forensic Guidance: For complete forensic telemetry workflows, consult our guide on PostgreSQL Extensions and Heap Memory Forensics.