CVE-2021-39226
Grafana Authentication Bypass Vulnerability
Description
CVE-2021-39226 is an authentication bypass vulnerability in Grafana, the widely used open-source analytics and monitoring platform, that allows both authenticated and unauthenticated users to view and delete all snapshot data. The vulnerability exposes the snapshot API endpoints to unauthorized access, potentially resulting in complete loss of dashboard snapshot data. Grafana is deployed extensively in enterprise environments for infrastructure monitoring and observability, making this vulnerability a significant threat to operational visibility. CISA has added CVE-2021-39226 to its Known Exploited Vulnerabilities catalog, and with an EPSS score of 94.3% (99th percentile), exploitation is near-certain for exposed instances.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorCWEs
Affected Products
| Vendor | Product | Version |
|---|---|---|
| grafana | grafana | < 7.5.11; >= 8.0.0, < 8.1.6 |
| fedoraproject | fedora | 34; 35 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
References
- http://www.openwall.com/lists/oss-security/2021/10/05/4(Mailing List, Third Party Advisory)
- https://github.com/grafana/grafana/commit/2d456a6375855364d098ede379438bf7f0667269(Patch)
- https://github.com/grafana/grafana/security/advisories/GHSA-69j6-29vr-p3j9(Exploit, Mitigation, Vendor Advisory)
- https://grafana.com/docs/grafana/latest/release-notes/release-notes-7-5-11/(Release Notes)
- https://grafana.com/docs/grafana/latest/release-notes/release-notes-8-1-6/(Release Notes)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DCKBFUSY6V4VU5AQUYWKISREZX5NLQJT/(Broken Link)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/E6ANHRDBXQT6TURLP2THM26ZPDINFBEG/(Broken Link)
- https://security.netapp.com/advisory/ntap-20211029-0008/(Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-39226(US Government Resource)
Weakness Type
CWE-287: Improper Authentication
CVE-2021-39226 exploits an improper authentication weakness in Grafana's snapshot API, where the endpoints responsible for viewing and deleting snapshot data fail to properly enforce authentication requirements. This allows both unauthenticated users and users with low-privilege accounts to access API endpoints that should require administrative credentials, enabling unauthorized data access and deletion.
Learn more: CWE-287 — Improper Authentication
Impact Analysis
CVE-2021-39226 poses a significant risk to organizations using Grafana for monitoring and analytics. The vulnerability is remotely exploitable over the network without authentication, requiring no user interaction and involving low attack complexity. An attacker can view all snapshot data, which may contain sensitive operational information, performance metrics, and infrastructure details that reveal the organization's technology stack and architecture. The ability to delete snapshots can destroy valuable monitoring data and audit trails. While the vulnerability does not directly enable code execution, the information disclosure can inform further attacks against the monitored infrastructure, and the data destruction capability impacts availability of historical monitoring data. With an EPSS score of 94.3% (99th percentile), this vulnerability is among the most actively exploited across all known CVEs.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2021-39226 in the wild by adding it to the Known Exploited Vulnerabilities catalog with a remediation deadline of September 15, 2022. The EPSS score of 94.3% (99th percentile) reflects near-certain exploitation activity. Grafana released a critical security fix announcement in October 2021, and public exploit information has been available since then. The exploit is straightforward, requiring only unauthenticated HTTP requests to the snapshot API endpoints. No specific ransomware campaigns are currently associated with this CVE.
Remediation
- Upgrade Grafana immediately: Per the CISA KEV required action, apply updates per vendor instructions. Upgrade to Grafana 7.5.11, 8.1.6, or later versions that address the authentication bypass as documented in the Grafana security blog post.
- Restrict access to the Grafana snapshot API: As an interim mitigation, configure a reverse proxy to block unauthenticated access to the snapshot API endpoints (/api/snapshots and related paths) until the upgrade can be completed.
- Audit snapshot data for unauthorized access: Review Grafana access logs for signs of unauthorized snapshot viewing or deletion that may have occurred before patching. Restore deleted snapshots from backups if available.
- Limit Grafana network exposure: Ensure that the Grafana web interface is not directly exposed to the public internet. Place Grafana behind a VPN or authentication proxy that requires valid credentials before reaching the application.
- Implement monitoring for Grafana API access: Set up alerting on Grafana API access patterns, particularly bulk snapshot access or deletion operations, to detect potential exploitation attempts in real-time.
Technical Details
CVE-2021-39226 is an authentication bypass vulnerability in Grafana's snapshot API endpoints. Grafana's snapshot feature allows users to create shareable, static representations of dashboard panels at a point in time. The vulnerability exists because certain API endpoints related to snapshot management do not properly check whether the requesting user is authenticated or has the appropriate permissions. Specifically, unauthenticated users can access endpoints that list, view, and delete snapshots by sending direct HTTP requests to the Grafana API without providing valid session credentials. The authentication check is missing or improperly implemented in the snapshot handler functions, allowing any network client that can reach the Grafana instance to enumerate and access all stored snapshots, including those created by administrative users. The fix in Grafana 7.5.11 and 8.1.6 adds proper authentication enforcement to all snapshot API endpoints.
Frequently Asked Questions
Is CVE-2021-39226 being actively exploited?
Yes. CISA has added CVE-2021-39226 to its Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. The EPSS score of 94.3% (99th percentile) indicates near-certain exploitation for exposed Grafana instances. No ransomware campaigns are currently associated with this vulnerability.
What products are affected by CVE-2021-39226?
CVE-2021-39226 affects Grafana versions prior to 7.5.11 and 8.1.6. All Grafana installations with the snapshot feature accessible from untrusted networks are vulnerable to the authentication bypass.
How do I fix CVE-2021-39226?
Upgrade Grafana to version 7.5.11, 8.1.6, or later. As an interim measure, restrict access to the snapshot API endpoints using a reverse proxy or network firewall. Ensure Grafana is not directly exposed to the public internet.
How severe is CVE-2021-39226?
CVE-2021-39226 is a critical authentication bypass that allows unauthenticated viewing and deletion of all Grafana snapshot data. With an EPSS score of 94.3% (99th percentile), it is among the most actively exploited vulnerabilities. While it does not enable direct code execution, the information disclosure and data destruction capabilities pose significant operational risk.
Need Help With Vulnerability Management?
Our security experts can help you prioritize and remediate vulnerabilities effectively.