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Intro: CVE-2026-49094
CVE-2026-49094 is a vulnerability in Elastic Kibana that allows an authenticated user with viewer-level access to cause a denial of service (DoS) by submitting an oversized input value to an analytics collections management endpoint. The flaw lies in the `Uncontrolled Resource Consumption (CWE-400)` pattern, specifically through Excessive Allocation (CAPEC-130).
When a low-privileged user sends a request with an abnormally large payload (e.g., a JSON object with massive arrays or deep nesting), Kibana’s input validation logic fails to enforce size limits. As a result, the Kibana process allocates excessive CPU cycles and memory—often exponentially scaling with the input size—until system resources are exhausted.
Because the request is processed before any resource throttling or rate limiting is applied, a single malicious request can monopolize the Kibana service. The impact is immediate: Kibana becomes unresponsive to all users, including administrators, and requires manual restart of the service to restore functionality.
The vulnerability affects all Kibana versions from `8.0.0` up to (but not including) 8.19.16, as confirmed by NIST’s NVD. Elastic has addressed the issue in version `8.19.16` (released May 28, 2026). No workaround is available for self‑managed instances other than upgrading.
This issue is particularly dangerous because it requires only viewer‑level access, a common role in many Kibana deployments. Exploitation can be performed via standard authenticated API calls, making it a low‑complexity attack with high availability impact.
The CVSS v3.1 base score is 6.5 (MEDIUM), with the vector string:
`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`.
DailyCVE Form
Platform: `Elastic Kibana`
Version: `8.0.0–8.19.15`
Vulnerability: `DoS (Resource Exhaustion)`
Severity: `MEDIUM (6.5)`
Date: `2026-05-28`
Prediction: `Already patched (2026-05-28)`
What Undercode Say
Analytics & detection commands
Monitor Kibana resource usage in real time
watch -n 1 'ps aux | grep kibana | grep -v grep | awk "{print \$2,\$3,\$4,\$6}"'
Check Kibana logs for oversized payload attempts
grep -i "oversized|payload|resource exhaustion" /var/log/kibana/kibana.log
Simulate a safe PoC (requires authenticated session)
curl -k -X POST "https://kibana-host/api/analytics/collections" \
-H "Authorization: Bearer $TOKEN" \
-H "Content-Type: application/json" \
-d '{"data": "'$(python -c 'print("A"1000000)')'"}'
How Exploit
- Obtain viewer‑level credentials (e.g., via phishing or weak password).
2. Identify the analytics collections management endpoint:
`POST /api/analytics/collections` (or similar).
- Craft a JSON payload with an excessively large string, array, or deeply nested object.
- Send the request using any HTTP client (e.g.,
curl). - Kibana will consume CPU/memory until it crashes, denying service to all users.
Protection
- Upgrade to Kibana `8.19.16` or later immediately.
- If upgrade is impossible, restrict viewer‑level access to only trusted users.
- Deploy a Web Application Firewall (WAF) to block requests exceeding a size threshold (e.g., > 10 MB).
- Implement network‑level rate limiting on the Kibana API endpoint.
- Monitor logs for abnormal resource spikes and restart Kibana automatically.
Impact
- Availability: Complete denial of service for all users.
- Operational: Manual intervention required to restart Kibana; potential data loss if logs are not flushed.
- Business: Monitoring and security operations disrupted, leading to missed alerts and degraded incident response.
- Risk: Low‑privilege attacker can take down the entire monitoring stack with a single request.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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