Detections
Analytics

Elasticsearch 8.18.x < 8.19.20 / 9.0.x < 9.4.5 / 9.5.x < 9.5.1 Information Disclosure (ESA-2026-141)

medium Nessus Plugin ID 344304

Synopsis

The remote host is missing a security update.

Description

The version of Elasticsearch installed on the remote host is 8.18.x prior to 8.19.20, or 9.0.x prior to 9.4.5, or 9.5.x prior to 9.5.1. It is, therefore, affected by a vulnerability as referenced in the ESA-2026-141 advisory.

 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') (CWE-444) in Elasticsearch can lead to information disclosure via HTTP Request Smuggling (CAPEC-33). Under specific proxy deployment configurations, a network attacker could obtain confidential responses intended for other authenticated users. (CVE-2026-78605)

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

Solution

Upgrade to Elasticsearch version 8.19.20, 9.4.5, or 9.5.1 or later as appropriate for your release branch.

See Also

http://www.nessus.org/u?6d15741b

Plugin Details

Severity: Medium

ID: 344304

File Name: elasticsearch_ESA-2026-141.nasl

Version: 1.1

Type: Combined

Agent: unix

Family: Misc.

Published: 9/9/2026

Updated: 9/9/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.62

CVSS v2

Risk Factor: Medium

Base Score: 5.4

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

CVSS Score Source: CVE-2026-78605

CVSS v3

Risk Factor: Medium

Base Score: 5.9

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

Vulnerability Information

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

Required KB Items: installed_sw/Elasticsearch

Patch Publication Date: 9/1/2026

Vulnerability Publication Date: 9/1/2026

Reference Information

CVE: CVE-2026-78605