CVE-2026-62390: Apache Kylin SQL Injection in Catalog Cache Refresh API
TL;DR - Critical SQL injection in Apache Kylin catalog refresh functionality. - Affects Apache Kylin 4.x through 5.0.3; upgrade to 5.0.4. - No confirmed public exploitation yet, but treat internet-exposed instances as urgent.
Vulnerability at a Glance
| Field | Value |
|---|---|
| CVE ID | CVE-2026-62390 |
| CVSS Score | 9.8 Critical |
| Attack Vector | Unknown from the provided NVD output; defenders should assume remote reachability if the backend API is exposed |
| Privileges Required | Unknown from available primary-source text |
| Patch Available | Yes, upgrade to Apache Kylin 5.0.4 |
CVE-2026-62390 is a critical SQL injection vulnerability in Apache Kylin. The public description states that a backend API used for refreshing the table catalog can cause attacker-controlled input to be injected into generated SQL. That places the issue squarely in the class of server-side input handling flaws that can be dangerous even when only administrative or internal functions are involved.
For practitioners, the important point is that the vendor has already identified a fixed release: Apache Kylin 5.0.4. If you run Kylin anywhere in production, especially where management interfaces are exposed beyond a tightly controlled admin network, this should move quickly into patch validation and upgrade planning. Because the publicly available technical detail is still limited, defenders should assume worst-case impact consistent with critical SQL injection until they verify their deployment specifics.
What Is This Vulnerability?
According to the NVD description, this issue is an “Improper Neutralization of Special Elements used in an SQL Command (‘SQL Injection’)” vulnerability in Apache Kylin. The vulnerable area is described as a backend API responsible for refreshing the table catalog, also referred to in the advisory context as the Catalog Cache Refresh API. In practical terms, that means untrusted input can influence SQL statements generated by the application during catalog refresh operations.
SQL injection in this context matters because catalog and metadata refresh paths often run with elevated database permissions compared with ordinary query execution. Even if Apache Kylin itself is primarily an analytics layer, any component that generates SQL against underlying metadata stores or connected data sources can become an attack surface if user-supplied values are not correctly sanitized or parameterized.
The published root-cause detail is limited to the vulnerability class and affected function. There is no reliable public write-up in the source material that explains the exact parameter, code path, or exploit string. That means defenders should avoid overconfidence. When the advisory says generated SQL can be influenced, assume that data exfiltration, unauthorized modification of metadata, or follow-on compromise of integrated systems may be possible depending on deployment architecture and the permissions granted to Kylin and its backing services.
Where technical specifics are unknown, the safe operational assumption is that any workflow invoking table catalog refresh should be considered sensitive until patched. If your environment exposes that API to non-admin users, automation accounts, or shared platform roles, reduce access immediately while preparing the upgrade.
Who Is Affected?
The disclosed affected range is Apache Kylin 4.x through 5.0.3. The vendor guidance and advisory text both state that the issue affects “from 4 through 5.0.3” and that users should upgrade to version 5.0.4. If you are running any 4.x release or Apache Kylin 5.0.0, 5.0.1, 5.0.2, or 5.0.3, you should consider the instance affected unless you have explicit confirmation of a backported fix from your own distribution source.
The available source material does not distinguish between edition variants, packaging methods, or deployment topologies. It also does not state whether only specific modules are affected. Because the flaw is tied to a backend API for catalog refresh, any deployment that includes that functionality should be treated as exposed. If you use Apache Kylin as part of a larger analytics stack, review whether embedded, containerized, or vendor-repackaged versions are still based on vulnerable upstream builds.
Organizations most at risk are those with internet-reachable Kylin management interfaces, broad internal access to administrative APIs, or service accounts with high-privilege database access. Even if the vulnerable endpoint is not publicly exposed, internal exploitation remains a concern in environments where analysts, developers, or automation tools can trigger refresh operations.
If you do not know your exact version, verify it now from deployment manifests, container tags, package metadata, or the Kylin application interface. In the absence of version clarity, defenders should assume vulnerable status for any Kylin deployment built before or not explicitly upgraded to 5.0.4.
CVSS Score Breakdown
The reported CVSS v3.x base score is 9.8, which falls in the Critical range. That score strongly suggests a vulnerability with very high potential impact and likely low exploitation complexity. However, the exact vector string was not available in the provided NVD output, so any interpretation of individual metric values must be framed carefully.
A 9.8 score commonly aligns with conditions such as network accessibility, low attack complexity, no privileges required, and high impact on confidentiality, integrity, and availability. That said, those specific values are not confirmed here because the vector string was not returned in the source material provided. Practitioners should therefore avoid citing unverified metric components in internal risk documentation.
Even without the vector string, the operational meaning is straightforward: upstream and NVD consider this bug severe enough to warrant rapid remediation. SQL injection flaws often earn high scores because successful exploitation can let an attacker read sensitive data, alter application state, or affect backend systems through the application’s own trust relationships.
In environments where Kylin connects to sensitive data platforms or uses privileged service accounts, the real-world impact can exceed what a single product-centric score conveys. Review not just the Kylin node itself, but also the reachable databases, metadata stores, and administrative workflows connected to it.
Exploitation Status
At the time of the reviewed sources, there is no verified public proof-of-concept identified for CVE-2026-62390. The research note also found no evidence of confirmed in-the-wild exploitation. In addition, the CVE is not listed in CISA’s Known Exploited Vulnerabilities catalog at the time of check.
That is useful context, but it should not be misread as a sign of low urgency. Lack of a public PoC often only delays broad opportunistic scanning; it does not prevent private exploit development. SQL injection is a mature and well-understood class of weakness, so once the vulnerable endpoint and parameter handling are mapped, exploit construction may be straightforward for capable attackers.
For defenders, the correct status statement is: no confirmed public PoC located, no confirmed active exploitation found in reviewed sources, and not in CISA KEV as of 2026-07-14. If your organization requires an exploitation-based prioritization model, note that the absence of public exploitation data should be offset by the critical severity, clear vendor fix, and the possibility that exposed management APIs are easier to abuse than initial disclosures suggest.
Where exposure is external or accessible from semi-trusted internal segments, assume exploit attempts may appear quickly after disclosure even if no public tooling has yet surfaced.
How to Detect It
Start by identifying all Apache Kylin instances and determining whether any expose administrative or backend APIs related to catalog or table refresh. If you have reverse proxies, API gateways, WAFs, or ingress controllers in front of Kylin, review request logs for unusual refresh-related requests, especially those containing SQL metacharacters, nested quoting, comment markers, or unexpectedly long parameter values.
Because the public advisory does not provide the exact endpoint path or parameter name, detection must be behavior-based rather than signature-perfect. Focus on requests tied to table catalog refresh workflows that include suspicious characters such as single quotes, semicolons, SQL comments, boolean conditions, or time-delay expressions. Also watch for anomalous failures or SQL syntax errors in Kylin server logs and connected database logs shortly after refresh API calls.
Technical Notes
Example grep patterns for suspicious application or proxy logs:
grep -RniE "refresh|catalog|table" /var/log/nginx/ /var/log/httpd/ /opt/kylin/logs/ 2>/dev/null
grep -RniE "('|%27|--|;|/*|\bunion\b|\bselect\b|\bor\b\s+1=1|\bsleep\s*\()" /var/log/nginx/ /var/log/httpd/ /opt/kylin/logs/ 2>/dev/null
Example Splunk-style query for suspected exploit attempts against Kylin-facing web logs:
index=web_logs (kylin OR "/kylin")
("refresh" OR "catalog" OR "table")
("\" OR "'" OR "%27" OR "--" OR "/*" OR "union" OR "select" OR "sleep(" OR "or 1=1")
| stats count by src_ip, uri_path, http_method, status
| sort - count
Example generic regex pattern to flag suspicious refresh API requests in proxy logs:
(?i)(refresh|catalog|table).*(%27|'|--|/*|;|\bunion\b|\bselect\b|\bor\b\s+1=1|\bsleep\s*\()
In database logs, look for failed statements or unusual catalog-related queries generated by the Kylin service account after inbound refresh requests. If detailed SQL logging is enabled on the backend store, correlate Kylin-originating connections with syntax errors, comment markers, stacked statements, or query fragments that do not match normal refresh behavior. Exact log messages vary by backend, so build environment-specific detections rather than relying on one universal string.
Mitigation and Patching
The vendor-recommended fix is to upgrade Apache Kylin to version 5.0.4. This is the only explicitly confirmed remediation in the primary-source material. If you are on any 4.x release through 5.0.3, treat the deployment as vulnerable and plan an expedited upgrade. Where change control requires staging, prioritize systems with externally reachable admin paths or broad internal access first.
If immediate patching is not possible, reduce exposure around the backend API used for catalog refresh. Restrict access to Kylin management and API interfaces to trusted administrative networks only. Place the service behind an allowlist on your reverse proxy or VPN, disable unnecessary automation that invokes catalog refresh, and review whether database credentials used by Kylin can be temporarily reduced in scope without breaking operations. These are compensating controls, not substitutes for the fixed release.
Because the exact vulnerable parameter and endpoint are not fully documented in the provided sources, generic WAF signatures should be treated as partial risk reduction only. Do not assume a WAF alone will block exploitation. Also review database and metadata permissions assigned to the Kylin service account; least privilege can reduce blast radius if exploitation occurs before patching.
Technical Notes
If you deploy Apache Kylin from extracted release archives, the upgrade will usually involve replacing the application with the 5.0.4 release and following your standard service restart and validation process. A generic upgrade workflow may look like this:
# Example only: adapt paths and service names to your environment
curl -LO https://downloads.apache.org/kylin/apache-kylin-5.0.4-bin.tar.gz
tar -xzf apache-kylin-5.0.4-bin.tar.gz
systemctl stop kylin
mv /opt/kylin /opt/kylin.bak.$(date +%F)
mv apache-kylin-5.0.4-bin /opt/kylin
systemctl start kylin
If you run Kylin in containers, update the image tag or internal artifact reference to the build based on 5.0.4, then redeploy through your normal pipeline. Validate the running version after rollout from the UI, API, image metadata, or deployment manifest.
Example temporary NGINX access restriction for an admin or API path while you patch:
location /kylin/ {
allow 10.0.0.0/8;
allow 192.168.0.0/16;
deny all;
proxy_pass http://kylin_backend;
}
After patching, confirm that all nodes are on 5.0.4, remove vulnerable instances from load balancers, and monitor for continued suspicious requests. If exploit attempts were detected before the patch window, investigate for unauthorized metadata changes, unexpected refresh operations, or abnormal database activity originating from Kylin.
References
The primary public sources consistently describe CVE-2026-62390 as a critical SQL injection flaw in Apache Kylin’s catalog refresh functionality, affecting 4.x through 5.0.3 and fixed in 5.0.4. The NVD and CVE records provide the authoritative identifiers and severity context, while the oss-security advisory confirms the vulnerable area, fix version, and Apache tracking ID.
Because detailed exploit mechanics are not yet public in the reviewed material, defenders should rely on vendor-confirmed facts and avoid speculative IOC claims. For incident handling and remediation planning, the references below are the best starting point for validation and future updates.
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62390
- CVE Record: https://www.cve.org/CVERecord?id=CVE-2026-62390
- Apache advisory thread: https://lists.apache.org/thread/zdrj93txvdjj07f88s43d2pcg2gomvjc
- oss-security advisory mirror: http://www.openwall.com/lists/oss-security/2026/07/14/4
- Apache JIRA issue KYLIN-6089: https://issues.apache.org/jira/browse/KYLIN-6089
- Apache Kylin official site: https://kylin.apache.org/
- Apache project page: https://projects.apache.org/project.html?kylin=
For further understanding of SQL injection vulnerabilities, you may refer to our article on what is SQL injection. Also, consider looking into the importance of maintaining a secure chain of custody for your data in our piece on what is chain of custody.
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