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CVE-2026-102408

Inefficient Regular Expression Complexity in Elasticsearch Leading to Denial of Service

No known exploitation. EPSS puts it in the 28th percentile. A vendor fix is available.

CVSS 3.14.3MediumEPSS percentile28th0.3% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
No public exploit knownFixVendor fixNo build named by the sources

Published Updated Sources: CVE.org, NVD

NVD CVE.org

What to do

The vendor has published a fix. Version details are below where the sources state them.

  • ElasticsearchAffected: ≥ 8.19.0, ≤ 8.19.21Upgrade to: after 8.19.21Affected: ≥ 9.1.0, ≤ 9.3.8Upgrade to: after 9.3.8Affected: ≥ 9.4.0, ≤ 9.4.7Upgrade to: after 9.4.7Affected: ≥ 9.5.0, ≤ 9.5.4Upgrade to: after 9.5.4Stated by: CVE record

Versions as the sources state them. Full version matrix after sign-in

Check it yourselfA free OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Request an assessment to establish which checks fit your systems.

What it is

From the CVE record

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.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS28th
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

No public exploit or proof of concept found in the sources we track.

EPSS

0.3% chance of exploitation activity in the next 30 days, which ranks it in the 28th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

9 events over 16 days, from the signal feeds we watch.

  1. OpenVAS check added
  2. Patch availablerecord updated
  3. Record updated
  4. Publishedweakness classified, att&ck mapped, record updated, record updated

Affected products

And 1 more affected product. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

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

Scored 4.3 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required LowRequires basic user-level privileges
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality NoneNo confidentiality impact
  • Integrity NoneNo integrity impact
  • Availability LowReduced performance or intermittent disruption of service

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

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We'll flag the next CVE, public exploit or patch for Elasticsearch, not every advisory.