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Fencer Intel
medium 4.3

CVE-2026-102408 json

Inefficient Regular Expression Complexity in Elasticsearch Leading to Denial of Service

published last mo. modified 26d ago also BIT-elasticsearch-2026-102408 , EUVD-2026-93929

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 28%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami elasticsearch 8.19.22, 9.4.8, 9.5.5
  • elasticsearch elasticsearch 8.19.22, 9.4.8, 9.5.5
  • elastic elasticsearch 8.19.22, 9.4.8, 9.5.5
  • org.elasticsearch elasticsearch 8.19.22, 9.4.8, 9.5.5

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-102408 updated cvss 4.3

elasticsearch: elasticsearch: Denial of Service via crafted regular expressions in ES|QL CHUNK function

  • Red Hat OpenShift AI (RHOAI) rhoai/odh-feature-server-rhel9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Quay 3 quay/quay-rhel8, quay/quay-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
OSV 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
bitnami elasticsearch
>=8.19.0, <8.19.22
>=9.1.0, <9.4.8
>=9.5.0, <9.5.5
8.19.22
9.4.8
9.5.5

Affected products

  • Elastic Elasticsearch

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.