CVE-2026-3172
Description
A flaw was found in pgvector. A buffer overflow vulnerability in the parallel Hierarchical Navigable Small World (HNSW) index build process allows a database user to exploit this flaw. This can lead to the disclosure of sensitive data from other database relations or cause the database server to crash, resulting in a denial of service.
Statement
A buffer overflow during parallel HNSW index builds can be exploited by a database user, potentially leading to information disclosure from other database relations or a denial of service by crashing the database server, although the high impact on availability and confidentiality Red Hat Product Security team has rated this as having a moderate severity. This happens because, besides the low privileges required, to successfully exploit this flaw the attack needs to win a race condition among several worker threads which may be a task considered of a high complexity.
Mitigation
To mitigate this issue, restrict the use of parallel index builds in PostgreSQL. This can be achieved by setting the `max_parallel_workers_per_gather` parameter to `0` in the `postgresql.conf` file. This configuration change may impact the performance of other parallel operations within PostgreSQL. A restart of the PostgreSQL service is required for the changes to take effect.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.8 | N/A | 8.1 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of the product's implicit security policy. This can often be used to subvert any other security service.
Availability
Technical Impact: Modify Memory; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)
Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the product into an infinite loop.
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