CVE-2021-39226
CVE-2021-39226 is a security flaw in Grafana Labs Grafana. Attackers can get into Grafana Labs Grafana without a valid password. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 25 Aug 2022.[1]
Grafana Labs Grafana is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Grafana Labs has published a fix or advice.
Description
CISA calls it an authentication bypass in Grafana Labs Grafana. In its words: “Grafana contains an authentication bypass vulnerability that allows authenticated and unauthenticated users to view and delete all snapshot data, potentially resulting in complete snapshot data loss.”[1]
The CVE record adds: “Grafana is an open source data visualization platform. In affected versions unauthenticated and authenticated users are able to view the snapshot with the lowest database key by accessing the literal paths: /dashboard/snapshot/:key, or /api/snapshots/:key. If the snapshot "public_mode" configuration setting is set to true (vs default of false), unauthenticated users are able to delete the snapshot with the lowest database key by accessing the literal path: /api/snapshots-delete/:deleteKey. Regardless of the snapshot "public_mode" setting, authenticated users are able to delete the snapshot with the lowest database key by accessing the literal paths: /api/snapshots/:key, or /api/snapshots-delete/:deleteKey. The combination of deletion and viewing enables a complete walk through all snapshot data while resulting in complete snapshot data loss. This issue has been…”[2]
The underlying weakness is improper authentication (CWE-287), in MITRE’s list of common software weaknesses.
It scores 7.3 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Grafana Labs’s advisory has them[3]. CISA names the product as Grafana Labs Grafana.
Most families won’t have Grafana Labs Grafana; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 25 Aug 2022, 324 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 15 Sep 2022 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at over 99%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Grafana Labs has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Grafana Labs Grafana is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 15 Sep 2022 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.3.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at over 99%.[4] |
See also
Other Grafana Labs Grafana flaws
- CVE-2021-43798: path traversal ·
Other improper authentication flaws
- CVE-2026-105133, AhsayCBS: improper authentication ·
- CVE-2026-42018, JFrog Artifactory: improper authentication ·
- CVE-2026-82329, JFrog Artifactory: improper authentication ·
- CVE-2026-59822, BerriAI LiteLLM: improper authentication ·
- CVE-2023-49105, ownCloud: improper authentication ·
Added the same day
- CVE-2022-26352, dotCMS: unrestricted upload of file ·
- CVE-2022-24706, Apache CouchDB: insecure default initialization of resource ·
- CVE-2022-24112, Apache APISIX: authentication bypass ·
- CVE-2022-22963, VMware Tanzu Spring Cloud: function remote code execution ·
- CVE-2022-2294, WebRTC: heap buffer overflow ·
References
- ^ Cybersecurity and Infrastructure Security Agency. “Grafana Authentication Bypass Vulnerability”. Known Exploited Vulnerabilities Catalog, added 25 Aug 2022.
- ^ National Institute of Standards and Technology. “CVE-2021-39226 Detail”. National Vulnerability Database, published 5 Oct 2021.
- ^ Grafana Labs. Advisories and fixes: grafana.com, grafana.com, grafana.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.999, percentile 100.0, 31 Oct 2026.
- CVE Program. “CVE-2021-39226”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.