How severe is CVE-2026-72636?

CVE-2026-72636 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-72636 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-72636?

CVE-2026-72636 affects Elastic Elasticsearch. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-72636?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-72636 published?

CVE-2026-72636 was published on 2026-08-13 and last updated on 2026-09-01.

CVE-2026-72636

CVE-2026-72636 is a medium-severity vulnerability in Elastic Elasticsearch with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-674.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (34th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-674
Affected product: Elastic Elasticsearch
Published: 2026-08-13
Last modified: 2026-09-01

Description

Uncontrolled Recursion (CWE-674) in the Elasticsearch wildcard matching helper can lead to a denial of service via Excessive Allocation (CAPEC-130). The matcher used to resolve wildcard patterns against names is implemented recursively and had no bound on recursion depth or on the total number of match operations performed. A search request containing a wildcard pattern with a large number of wildcard groups, evaluated against a sufficiently long name, exhausts the thread stack. Elasticsearch treats a stack overflow as an unrecoverable condition and shuts the node down, so the request terminates the affected node rather than failing gracefully.

Frequently asked questions

What is CVE-2026-72636?: Uncontrolled Recursion (CWE-674) in the Elasticsearch wildcard matching helper can lead to a denial of service via Excessive Allocation (CAPEC-130). The matcher used to resolve wildcard patterns against names is implemented recursively and had no bound on recursion depth or on the total number of match operations performed. A search request containing a wildcard pattern with a large number of wildcard groups, evaluated against a sufficiently long name, exhausts the thread stack. Elasticsearch treats a stack overflow as an unrecoverable condition and shuts the node down, so the request terminates the affected node rather than failing gracefully.
How severe is CVE-2026-72636?: CVE-2026-72636 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-72636 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-72636?: CVE-2026-72636 affects Elastic Elasticsearch. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-72636?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-72636 published?: CVE-2026-72636 was published on 2026-08-13 and last updated on 2026-09-01.

References

https://discuss.elastic.co/t/elasticsearch-8-19-20-9-4-5-security-update-esa-2026-133/389499

Affected products (1)

cpe:2.3:a:elastic:elasticsearch:*:*:*:*:*:*:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

223.15.242.2 (ipv4-addr)