Elasticsearch 8.x < 8.19.20 / 9.0.x < 9.4.5 Multiple Vulnerabilities (ESA-2026-76 / ESA-2026-77 / ESA-2026-118 / ESA-2026-119 / ESA-2026-133)

medium Nessus Plugin ID 338341

Synopsis

The remote host is missing a security update.

Description

The version of Elasticsearch installed on the remote host is 8.x prior to 8.19.20, or 9.0.x prior to 9.4.5. It is, therefore, affected by multiple vulnerabilities as referenced in the ESA-2026-76, ESA-2026-77, ESA-2026-118, ESA-2026-119, and ESA-2026-133 advisories.

- Uncontrolled Recursion (CWE-674) in the Elasticsearch wildcard matching helper can lead to a denial of service via Excessive Allocation (CAPEC-130). The matcher used to resolve wildcard patterns against names is implemented recursively and had no bound on recursion depth or on the total number of match operations performed. A search request containing a wildcard pattern with a large number of wildcard groups, evaluated against a sufficiently long name, exhausts the thread stack. (CVE-2026-72636)

- Uncontrolled Recursion (CWE-674) in Elasticsearch can lead to denial of service via Input Data Manipulation (CAPEC-153). An authenticated user holding only low-privileged index creation permissions can submit a single request containing a specially crafted, malformed custom analysis definition that is resolved recursively without a cycle or depth check, exhausting the thread stack and terminating the affected node.
(CVE-2026-72638)

- Uncontrolled Recursion (CWE-674) in Elasticsearch can lead to denial of service via Serialized Data with Nested Payloads (CAPEC-230). An authenticated user holding only read privileges on a single index can submit one specially crafted search request whose deeply nested structure is processed without a depth limit, exhausting the thread stack and terminating the affected node. (CVE-2026-72647)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Upgrade to Elasticsearch version 8.19.20 or 9.4.5 or later as appropriate for your release branch.

Plugin Details

Severity: Medium

ID: 338341

File Name: elasticsearch_ESA-2026-76.nasl

Version: 1.2

Type: Combined

Agent: unix

Family: Misc.

Published: 8/20/2026

Updated: 8/21/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.72

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

Vector: CVSS2#AV:N/AC:L/Au:S/C:N/I:N/A:C

CVSS Score Source: CVE-2026-72684

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:elastic:elasticsearch, cpe:/a:elasticsearch:elasticsearch

Required KB Items: installed_sw/Elasticsearch

Exploit Ease: No known exploits are available

Patch Publication Date: 8/13/2026

Vulnerability Publication Date: 8/13/2026

Reference Information

CVE: CVE-2026-72636, CVE-2026-72638, CVE-2026-72647, CVE-2026-72684, CVE-2026-72685

CWE: 407, 674, 770

Detections

Analytics