Inefficient Regular Expression Complexity in Elasticsearch Leading to Denial of Service
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.
CVE-2026-102408
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-102408
Elasticsearch
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "Elastic",
"product": "Elasticsearch",
"versions": [
{
"status": "affected",
"version": "8.19.0",
"versionType": "semver",
"lessThanOrEqual": "8.19.21"
},
{
"status": "affected",
"version": "9.1.0",
"versionType": "semver",
"lessThanOrEqual": "9.3.8"
},
{
"status": "affected",
"version": "9.4.0",
"versionType": "semver",
"lessThanOrEqual": "9.4.7"
},
{
"status": "affected",
"version": "9.5.0",
"versionType": "semver",
"lessThanOrEqual": "9.5.4"
}
],
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-102408
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #9575 · Revision 1
- Added to Heist Feed
- Publisher date