Listen to this Post
The CVE-2025-5307 vulnerability in OpenSearch exists within the query parser for the `query_string` functionality. When a specially crafted, complex query is submitted, it triggers an inefficient parsing algorithm, causing excessive consumption of CPU resources. This occurs because the parser enters a state of catastrophic backtracking when processing certain regular expressions or nested logical operators within the query input. The engine spends a disproportionate amount of time evaluating this single, malicious query, leading to severe resource exhaustion. This effectively renders the OpenSearch node unresponsive to other legitimate requests, achieving a Denial of Service condition. The flaw is exploitable remotely by any user with permissions to submit search queries.
Platform: OpenSearch
Version: <3.2.0
Vulnerability : Denial of Service
Severity: High
date: 2025-11-25
Prediction: 2025-12-09
What Undercode Say:
curl -X GET "https://localhost:9200/my-index/_search" -H 'Content-Type: application/json' -d'
{
"query": {
"query_string": {
"query": "aaaaaaaaaaaaaaaaaaaaaaaaaaaa! OR"
}
}
}'
// Pseudocode for inefficient parsing loop
while (parseComplexExpression(query)) {
// Excessive backtracking occurs here
}
How Exploit:
Craft malicious query_string.
Send to OpenSearch endpoint.
CPU exhausts, service denies.
Protection from this CVE
Upgrade to 3.2.0.
Implement query rate-limiting.
Use query validation rules.
Impact:
Cluster unresponsiveness.
High CPU utilization.
Service downtime.
🎯Let’s Practice Exploiting & Learn Patching For Free:
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
