CVE-2026-103009: Authorization Bypass Through User-Controlled Key (CWE-639) in Elasticsearch can lead to Information Disclosure

Routine

HIGH 7.1UPGRADE

CVE-2026-103009 is a high-severity flaw (CVSS 7.1) affecting elasticsearch. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Authorization Bypass Through User-Controlled Key (CWE-639) in Elasticsearch can lead to Information Disclosure via a specially crafted cross-cluster search request that references an unauthorized shard identifier. Elasticsearch contains an authorization bypass weakness in its handling of cross-cluster search requests made through the Remote Cluster Security (RCS) 2.0 model. An authorization check validates a request against one identifying attrib

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 86%)
CISA exploited list	No
Weakness	CWE-639
Published	2026-10-06
Last modified	2026-10-09

Publisher (CNA): Elastic · Vendor: elastic

Last updated 2026-10-09 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-06 20:17 UTCPublished CVE record published
2026-10-09 13:13 UTCUpdated Record last modified

elastic elasticsearch UPGRADE

Affected: >= 8.13.0 and < 8.19.23 · >= 9.0.0 and < 9.4.8 · >= 9.5.0 and < 9.5.5

Fixed in: 8.19.23, 9.4.8, 9.5.5

Safe to downgrade to: a release before 8.13.0

1. Check installed version

apt-cache policy elasticsearch || rpm -q elasticsearch || elasticsearch --version

2. UPGRADE to 8.19.23 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade elasticsearch

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade elasticsearch

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 8.13.0 (Debian / Ubuntu)

apt-cache madison elasticsearch sudo apt install elasticsearch=<VERSION_BEFORE_8.13.0> sudo apt-mark hold elasticsearch

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list elasticsearch sudo dnf downgrade elasticsearch-<VERSION_BEFORE_8.13.0> sudo dnf versionlock add elasticsearch

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Advisories and coverage

Official advisories

Elastic Security Announcements: Elasticsearch 8.19.23, 9.4.8, 9.5.5 Security Update (ESA-2026-199) 2026-10-06

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-103009?

elasticsearch: upgrade to 8.19.23, 9.4.8, 9.5.5. Exact commands for each OS are on this page.

Is CVE-2026-103009 being exploited?

CVE-2026-103009 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-103009 affect?

CVE-2026-103009 affects elasticsearch. Severity is high (CVSS 7.1). Authorization Bypass Through User-Controlled Key (CWE-639) in Elasticsearch can lead to Information Disclosure via a specially crafted cross-cluster search request that references an unauthorized shard identifier. Elasticsearch contains an

How urgent is CVE-2026-103009?

Priority 28/100. High severity

Software pages

Elasticsearch vulnerabilities

Related CVEs

CVE-2026-56148 MEDIUM 6.5 UPGRADE Uncontrolled Recursion (CWE-674) in Elasticsearch can lead to a denial of service via Excessive Allocation (CA
CVE-2026-49090 MEDIUM 6.5 UPGRADE Uncontrolled Resource Consumption (CWE-400) in Elasticsearch can lead to a denial of service via Excessive All
CVE-2026-56149 MEDIUM 4.9 UPGRADE Allocation of Resources Without Limits or Throttling (CWE-770) in Elasticsearch can lead to a denial of servic
CVE-2026-56145 MEDIUM 6.5 UPGRADE Uncontrolled Resource Consumption (CWE-400) in Elasticsearch can lead to denial of service via Excessive Alloc
CVE-2026-63136 MEDIUM 6.5 UPGRADE Uncontrolled Resource Consumption (CWE-400) in Elasticsearch can lead to denial of service via Excessive Alloc

References

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