CVE-2021-27738 | Improper Access Control to Streaming Coordinator & SSRF

All request mappings in `StreamingCoordinatorController.java` handling `/kylin/api/streaming_coordinator/*` REST API endpoints did not include any security checks, which allowed an unauthenticated user to issue arbitrary requests, such as assigning/unassigning of streaming cubes, creation/modification and deletion of replica sets, to the Kylin Coordinator. For endpoints accepting node details in HTTP message body, unauthenticated (but limited) server-side request forgery (SSRF) can be achieved. This issue affects Apache Kylin Apache Kylin 3 versions prior to 3.1.2.

Published: 2022-01-06 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-27738 is rated Moderate Risk (58.6/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.18%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-27738

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-12-25 2.94% 2.18% -0.75%
2 2025-11-21 2.24% 2.94% +0.70%
3 2025-11-18 — 2.24% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-27738

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-27738

GitHub Security Advisory for CVE-2021-27738

GHSA-wrx7-qgmj-mf2q · Severity: medium · Ecosystem: maven — Server-Side Request Forgery in Apache Kylin

Affected software / configurations for CVE-2021-27738

Vendor Product Version Raw CPE
apache kylin >= 3.0.0, < 3.1.2 cpe:2.3:a:apache:kylin:*:*:*:*:*:*:*:*

References for CVE-2021-27738

cvelogic Threat Intelligence