Uncontrolled Recursion in Elasticsearch Wildcard Matching Leading to Denial of Service (CVE-2026-72636)
CVE-2026-72636 is a medium severity vulnerability in Elasticsearch affecting versions 8.0.0 up to but not including 8.19.20 and 9.0.0 up to but not including 9.4.5. It involves uncontrolled recursion in the wildcard matching helper, which can cause a denial of service by exhausting the thread stack and shutting down the node. This occurs when a search request contains a wildcard pattern with many wildcard groups evaluated against a long name, leading to a stack overflow that Elasticsearch treats as unrecoverable.
AI Analysis
Technical Summary
This vulnerability arises from the recursive implementation of the wildcard matching helper in Elasticsearch, which lacks limits on recursion depth and the number of match operations. When a crafted search request with a complex wildcard pattern is processed, it can cause excessive stack consumption, resulting in a stack overflow. Elasticsearch nodes encountering this condition shut down instead of failing gracefully, causing denial of service. The issue affects Elasticsearch versions >=8.0.0 <8.19.20 and >=9.0.0 <9.4.5. A patch is available to address this vulnerability.
Potential Impact
Exploitation of this vulnerability leads to denial of service by crashing Elasticsearch nodes due to stack overflow caused by uncontrolled recursion in wildcard pattern matching. This results in node shutdowns, disrupting service availability. There is no indication of data compromise or other impacts beyond denial of service.
Mitigation Recommendations
A patch is available for this vulnerability. Users should upgrade Elasticsearch to versions 8.19.20 or later, or 9.4.5 or later, where this issue is fixed. No additional mitigations are specified or required beyond applying the official fix.
Uncontrolled Recursion in Elasticsearch Wildcard Matching Leading to Denial of Service (CVE-2026-72636)
Description
CVE-2026-72636 is a medium severity vulnerability in Elasticsearch affecting versions 8.0.0 up to but not including 8.19.20 and 9.0.0 up to but not including 9.4.5. It involves uncontrolled recursion in the wildcard matching helper, which can cause a denial of service by exhausting the thread stack and shutting down the node. This occurs when a search request contains a wildcard pattern with many wildcard groups evaluated against a long name, leading to a stack overflow that Elasticsearch treats as unrecoverable.
Affected software
pkg:bitnami/elasticsearchRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability arises from the recursive implementation of the wildcard matching helper in Elasticsearch, which lacks limits on recursion depth and the number of match operations. When a crafted search request with a complex wildcard pattern is processed, it can cause excessive stack consumption, resulting in a stack overflow. Elasticsearch nodes encountering this condition shut down instead of failing gracefully, causing denial of service. The issue affects Elasticsearch versions >=8.0.0 <8.19.20 and >=9.0.0 <9.4.5. A patch is available to address this vulnerability.
Potential Impact
Exploitation of this vulnerability leads to denial of service by crashing Elasticsearch nodes due to stack overflow caused by uncontrolled recursion in wildcard pattern matching. This results in node shutdowns, disrupting service availability. There is no indication of data compromise or other impacts beyond denial of service.
Mitigation Recommendations
A patch is available for this vulnerability. Users should upgrade Elasticsearch to versions 8.19.20 or later, or 9.4.5 or later, where this issue is fixed. No additional mitigations are specified or required beyond applying the official fix.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- BIT-elasticsearch-2026-72636
- Osv Schema Version
- 1.6.2
- Aliases
- ["CVE-2026-72636"]
- Ecosystems
- ["Bitnami"]
- Database Specific Severity
- Medium
- Cvss Version
- null
Threat ID: 6a85b4b2acd9273b492514cb
Added to database: 08/19/2026, 13:50:42 UTC
Last enriched: 08/19/2026, 14:12:52 UTC
Last updated: 08/19/2026, 23:52:00 UTC
Views: 2
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