CVE-2026-102408
Inefficient Regular Expression Complexity in Elasticsearch Leading to Denial of Service
Description
Inefficient Regular Expression Complexity (CWE-1333) in Elasticsearch can lead to denial of service via Regular Expression Exponential Blowup (CAPEC-492). The ES|QL CHUNK function's recursive chunking strategy accepts a list of user-supplied regular expressions used as text-splitting separators, without validating their computational complexity or bounding their execution time. An authenticated user with read access to any text-based index can submit a specially crafted regular expression that triggers catastrophic backtracking, consuming excessive CPU on Elasticsearch worker threads and degrading query throughput for other tenants on the affected node. The cluster does not crash as a result of this issue.
INFO
Published Date :
Oct. 6, 2026, 8:17 p.m.
Last Modified :
Oct. 13, 2026, 6:48 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 271b6943-45a9-4f3a-ab4e-976f3fa05b5a | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Apply security patches for Elasticsearch.
- Validate regular expression complexity.
- Limit regular expression execution time.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-102408.
| URL | Resource |
|---|---|
| https://discuss.elastic.co/t/elasticsearch-8-19-22-9-4-8-and-9-5-5-security-update-esa-2026-189/390862 | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-102408 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-102408
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-102408 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-102408 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Oct. 13, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:elastic:elasticsearch:*:*:*:*:*:*:*:* versions from (including) 9.5.0 up to (excluding) 9.5.5 *cpe:2.3:a:elastic:elasticsearch:*:*:*:*:*:*:*:* versions from (including) 8.19.0 up to (excluding) 8.19.22 *cpe:2.3:a:elastic:elasticsearch:*:*:*:*:*:*:*:* versions from (including) 9.1.0 up to (excluding) 9.4.8 Added Reference Type Elastic: https://discuss.elastic.co/t/elasticsearch-8-19-22-9-4-8-and-9-5-5-security-update-esa-2026-189/390862 Types: Vendor Advisory -
New CVE Received by [email protected]
Oct. 06, 2026
Action Type Old Value New Value Added Description Inefficient Regular Expression Complexity (CWE-1333) in Elasticsearch can lead to denial of service via Regular Expression Exponential Blowup (CAPEC-492). The ES|QL CHUNK function's recursive chunking strategy accepts a list of user-supplied regular expressions used as text-splitting separators, without validating their computational complexity or bounding their execution time. An authenticated user with read access to any text-based index can submit a specially crafted regular expression that triggers catastrophic backtracking, consuming excessive CPU on Elasticsearch worker threads and degrading query throughput for other tenants on the affected node. The cluster does not crash as a result of this issue. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-1333 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/102xxx/CVE-2026-102408.json">CVE-2026-102408</a> Added Reference https://discuss.elastic.co/t/elasticsearch-8-19-22-9-4-8-and-9-5-5-security-update-esa-2026-189/390862 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Oct. 06, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-102408', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-10-06T19:55:55.653697Z'}