CVE-2026-2003: PostgreSQL Information Disclosure Flaw

CVE-2026-2003 Overview

CVE-2026-2003 is an information disclosure vulnerability in PostgreSQL caused by improper validation of the oidvector data type. An authenticated database user can leverage the flaw to disclose a small number of bytes from server memory. The PostgreSQL Global Development Group has not ruled out attacks that arrange for confidential data to appear in the leaked bytes, though such scenarios are considered unlikely. The vulnerability is tracked under CWE-1287: Improper Validation of Specified Type of Input and affects all PostgreSQL versions prior to 18.2, 17.8, 16.12, 15.16, and 14.21.

Critical Impact
Authenticated PostgreSQL users can read small fragments of server process memory by submitting crafted oidvector input, potentially exposing data from adjacent allocations.

Affected Products

PostgreSQL versions before 18.2
PostgreSQL versions before 17.8 and 16.12
PostgreSQL versions before 15.16 and 14.21

Discovery Timeline

2026-02-12 - CVE-2026-2003 published to NVD
2026-02-20 - Last updated in NVD database

Technical Details for CVE-2026-2003

Vulnerability Analysis

The vulnerability stems from insufficient validation of values supplied for PostgreSQL's oidvector type. The oidvector type stores a one-dimensional array of object identifiers (OIDs) and is used internally by the system catalogs to represent things like function argument type lists. When PostgreSQL parses or processes an attacker-influenced oidvector value, it fails to fully verify the structure of the input. The result is a bounded read past the intended buffer that returns a small number of bytes from the backend process's address space to the caller.

Exploitation requires an authenticated database session with permissions to invoke the relevant functionality. The attack does not require user interaction and can be performed remotely against any reachable PostgreSQL instance. Impact is limited to confidentiality of a small memory window per request, with no integrity or availability impact. The PostgreSQL project rates the practical risk as low because the leaked bytes are unlikely to consistently contain sensitive material, but repeated probing across many queries cannot be excluded.

Root Cause

The defect is an input validation weakness in the oidvector type handling path. PostgreSQL accepts the value without enforcing all structural invariants expected by downstream code, so a subsequent read accesses memory beyond the validated region. This is consistent with [CWE-1287], where the type check is too permissive for the operation that follows.

Attack Vector

A logged-in database user submits a crafted value typed as oidvector through standard SQL interfaces. The server processes the value and returns query results that include a small slice of memory bytes adjacent to the input buffer. No elevated privileges, no local access, and no user interaction are required beyond an authenticated session.

No public proof-of-concept code, exploit, or technical write-up describing the precise crafted input has been published. Refer to the PostgreSQL Security Advisory for vendor-supplied technical details.

Detection Methods for CVE-2026-2003

Indicators of Compromise

Repeated queries from a single role that reference oidvector columns, casts to oidvector, or system catalogs such as pg_proc.proargtypes and pg_index.indkey in unusual patterns.
Application or analytics roles issuing ad-hoc SQL that constructs or casts oidvector literals — behavior atypical for service accounts.
Bursts of short, similar queries from the same session attempting to harvest output bytes across many invocations.

Detection Strategies

Enable PostgreSQL statement logging (log_statement = 'all' or pg_stat_statements) and alert on queries containing ::oidvector casts or direct manipulation of oidvector values from non-administrative roles.
Baseline normal catalog access patterns per role and flag deviations, especially repeated reads of internal type metadata.
Correlate database audit logs with network telemetry to identify clients issuing high volumes of catalog or type-conversion queries.

Monitoring Recommendations

Forward PostgreSQL logs and pgaudit output to a centralized SIEM and retain at least 90 days for retrospective hunting.
Track the PostgreSQL server version reported by SELECT version() across the fleet and alert on instances still running pre-patch builds.
Monitor for new or unexpected database roles, particularly any granted CONNECT privileges on production databases.

How to Mitigate CVE-2026-2003

Immediate Actions Required

Upgrade affected clusters to PostgreSQL 18.2, 17.8, 16.12, 15.16, or 14.21, matching your current major version.
Inventory all PostgreSQL instances, including managed cloud database services, and confirm vendor patch status for each.
Review database role grants and revoke CONNECT or query privileges from accounts that do not require them.
Enable query auditing on production databases to support post-patch hunting for prior abuse.

Patch Information

The PostgreSQL Global Development Group has released fixed builds in the 14.21, 15.16, 16.12, 17.8, and 18.2 maintenance releases. Apply the minor release that corresponds to your installed major version. Restart the PostgreSQL service after upgrade so all backend processes load patched code. Consult the PostgreSQL Security Advisory for download links and full release notes.

Workarounds

Restrict database access to trusted networks using pg_hba.conf and network-layer controls until patches are applied.
Remove unnecessary login roles and enforce strong authentication for all remaining accounts.
Apply least-privilege grants so general application roles cannot issue ad-hoc SQL against system catalogs.

bash

# Example: verify installed PostgreSQL version and patch status
psql -U postgres -c "SELECT version();"

# Debian/Ubuntu — apply vendor-provided update
sudo apt update && sudo apt install --only-upgrade postgresql
sudo systemctl restart postgresql

# RHEL/Rocky/Alma — apply vendor-provided update
sudo dnf update postgresql-server
sudo systemctl restart postgresql