CVE-2026-102408Inefficient Regular Expression Complexity in Elasticsearch Leading to Denial of Service
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 4.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- Weakness (CWE)
- CWE-1333
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- elastic
- NVD analysis
- Analyzed
- Record last updated
- Oct 6, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Elastic Elasticsearch elastic:elasticsearch (from the name) | from 8.19.0 through 8.19.21; from 9.1.0 through 9.3.8; from 9.4.0 through 9.4.7; from 9.5.0 through 9.5.4 | CNA record |
elastic elasticsearch elastic:elasticsearch | from 8.19.0 before 8.19.22; from 9.1.0 before 9.4.8; from 9.5.0 before 9.5.5 | NVD |
References
- https://discuss.elastic.co/t/elasticsearch-8-19-22-9-4-8-and-9-5-5-security-update-esa-2026-189/390862vendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.