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CVE-2026-102408

MEDIUM 4.3

Published 2026-10-06 · Last modified 2026-10-06

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.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 28th percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

4.3CVSS 3.1 · MEDIUM

  • ConfidentialityNone
  • IntegrityNone
  • AvailabilityLow

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ⚠Privileges: Requires a low-privilege account
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

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Data snapshot:

Affected

Vendors Elastic

Products Elasticsearch

Weakness (CWE)

  • CWE-1333: Inefficient Regular Expression Complexity

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

References and research data (JSON)

Vendor product assessments

  • rhoai/odh-feature-server-rhel9 as a component of Red Hat OpenShift AI (RHOAI) · known affected

    Vendor assessment for this product only.

    pkg:oci/odh-feature-server-rhel9?repository_url=registry.redhat.io/rhoai/odh-feature-server-rhel9

    • workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-102408 · Updated 2026-10-08T06:48:41+00:00
  • quay/quay-rhel8 as a component of Red Hat Quay 3 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/quay-rhel8?repository_url=registry.redhat.io/quay/quay-rhel8

    Red Hat · CVE-2026-102408 · Updated 2026-10-08T06:48:41+00:00
  • quay/quay-rhel9 as a component of Red Hat Quay 3 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:oci/quay-rhel9?repository_url=registry.redhat.io/quay/quay-rhel9

    Red Hat · CVE-2026-102408 · Updated 2026-10-08T06:48:41+00:00

Known Affected Software Configurations

VendorProductVersion range
ElasticElasticsearch≥ 8.19.0 and < 8.19.22
ElasticElasticsearch≥ 9.1.0 and < 9.4.8
ElasticElasticsearch≥ 9.5.0 and < 9.5.5

All CVSS metrics

  • MEDIUM 4.3 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
  • MEDIUM 4.3 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

References

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS