CVE-2026-21720 (GCVE-0-2026-21720)
Vulnerability from cvelistv5
Published
2026-01-27 09:07
Modified
2026-08-27 17:22
Severity ?
VLAI Severity ?
EPSS score ?
Summary
Every uncached /avatar/:hash request spawns a goroutine that refreshes the Gravatar image. If the refresh sits in the 10-slot worker queue longer than three seconds, the handler times out and stops listening for the result, so that goroutine blocks forever trying to send on an unbuffered channel. Sustained traffic with random hashes keeps tripping this timeout, so goroutine count grows linearly, eventually exhausting memory and causing Grafana to crash on some systems.
References
| URL | Tags | ||||
|---|---|---|---|---|---|
|
|||||
Impacted products
| Vendor | Product | Version | |||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grafana | grafana/grafana-enterprise |
Version: 3.0.0 ≤ |
|||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||||
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-21720",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-01-27T14:28:02.795937Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-400",
"description": "CWE-400 Uncontrolled Resource Consumption",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-703",
"description": "CWE-703 Improper Check or Handling of Exceptional Conditions",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-01-27T14:29:08.671Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
},
{
"affected": [
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:ceph_storage:7"
],
"defaultStatus": "unaffected",
"packageName": "rhceph/grafana-rhel9",
"product": "Red Hat Ceph Storage 7",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/a:redhat:ceph_storage:8"
],
"defaultStatus": "unaffected",
"packageName": "rhceph/grafana-rhel9",
"product": "Red Hat Ceph Storage 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:10"
],
"defaultStatus": "unaffected",
"packageName": "grafana",
"product": "Red Hat Enterprise Linux 10",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8"
],
"defaultStatus": "unaffected",
"packageName": "grafana",
"product": "Red Hat Enterprise Linux 8",
"vendor": "Red Hat"
},
{
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9"
],
"defaultStatus": "unaffected",
"packageName": "grafana",
"product": "Red Hat Enterprise Linux 9",
"vendor": "Red Hat"
}
],
"datePublic": "2026-01-27T09:07:04.758Z",
"descriptions": [
{
"lang": "en",
"value": "A flaw was found in Grafana. A remote attacker can exploit this vulnerability by sending a sustained volume of uncached /avatar/:hash requests. This action causes the system to create and block goroutines, which are lightweight concurrent functions, leading to a continuous increase in memory usage. Over time, this resource exhaustion can cause Grafana to crash, resulting in a Denial of Service (DoS)."
}
],
"metrics": [
{
"other": {
"content": {
"namespace": "https://access.redhat.com/security/updates/classification/",
"value": "Important"
},
"type": "Red Hat severity rating"
}
},
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"format": "CVSS"
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-772",
"description": "Missing Release of Resource after Effective Lifetime",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-15T01:19:55.276Z",
"orgId": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c",
"shortName": "redhat-SADP"
},
"references": [
{
"tags": [
"vdb-entry",
"x_refsource_REDHAT"
],
"url": "https://access.redhat.com/security/cve/CVE-2026-21720"
},
{
"name": "RHBZ#2433226",
"tags": [
"issue-tracking",
"x_refsource_REDHAT"
],
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2433226"
},
{
"tags": [
"x_sadp-csaf-vex"
],
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-21720.json"
}
],
"timeline": [
{
"lang": "en",
"time": "2026-01-27T10:01:10.677Z",
"value": "Reported to Red Hat."
},
{
"lang": "en",
"time": "2026-01-27T09:07:04.758Z",
"value": "Made public."
}
],
"title": "grafana: Grafana: Denial of Service via resource exhaustion from avatar requests",
"x_adpType": "supplier",
"x_generator": {
"engine": "sadp-cli 1.0.0"
}
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "grafana/grafana-enterprise",
"vendor": "Grafana",
"versions": [
{
"lessThan": "11.6.9",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
}
]
},
{
"defaultStatus": "unaffected",
"product": "grafana/grafana-enterprise",
"vendor": "Grafana",
"versions": [
{
"lessThan": "12.0.8",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
}
]
},
{
"defaultStatus": "unaffected",
"product": "grafana/grafana-enterprise",
"vendor": "Grafana",
"versions": [
{
"lessThan": "12.1.5",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
}
]
},
{
"defaultStatus": "unaffected",
"product": "grafana/grafana",
"vendor": "Grafana",
"versions": [
{
"lessThan": "11.6.9",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
}
]
},
{
"defaultStatus": "unaffected",
"product": "grafana/grafana",
"vendor": "Grafana",
"versions": [
{
"lessThan": "12.0.8",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
}
]
},
{
"defaultStatus": "unaffected",
"product": "grafana/grafana",
"vendor": "Grafana",
"versions": [
{
"lessThan": "12.1.5",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
}
]
},
{
"defaultStatus": "unaffected",
"product": "grafana/grafana-enterprise",
"vendor": "Grafana",
"versions": [
{
"lessThan": "12.2.3",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
}
]
},
{
"defaultStatus": "unaffected",
"product": "grafana/grafana",
"vendor": "Grafana",
"versions": [
{
"lessThan": "12.2.3",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
}
]
},
{
"defaultStatus": "unaffected",
"product": "grafana/grafana-enterprise",
"vendor": "Grafana",
"versions": [
{
"lessThan": "12.3.1",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
}
]
},
{
"defaultStatus": "unaffected",
"product": "grafana/grafana",
"vendor": "Grafana",
"versions": [
{
"lessThan": "12.3.1",
"status": "affected",
"version": "3.0.0",
"versionType": "semver"
}
]
}
],
"datePublic": "2026-01-27T09:03:09.893Z",
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"type": "text/markdown",
"value": "Every uncached /avatar/:hash request spawns a goroutine that refreshes the Gravatar image. If the refresh sits in the 10-slot worker queue longer than three seconds, the handler times out and stops listening for the result, so that goroutine blocks forever trying to send on an unbuffered channel. Sustained traffic with random hashes keeps tripping this timeout, so goroutine count grows linearly, eventually exhausting memory and causing Grafana to crash on some systems."
}
],
"value": "Every uncached /avatar/:hash request spawns a goroutine that refreshes the Gravatar image. If the refresh sits in the 10-slot worker queue longer than three seconds, the handler times out and stops listening for the result, so that goroutine blocks forever trying to send on an unbuffered channel. Sustained traffic with random hashes keeps tripping this timeout, so goroutine count grows linearly, eventually exhausting memory and causing Grafana to crash on some systems."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-08-27T17:22:47.419Z",
"orgId": "57da9224-a3e2-4646-9d0e-c4dc2e05e7da",
"shortName": "GRAFANA"
},
"references": [
{
"tags": [
"vendor-advisory"
],
"url": "https://grafana.com/security/security-advisories/cve-2026-21720"
}
],
"source": {
"discovery": "BUG_BOUNTY"
},
"title": "Unauthenticated DoS: avatar cache leaks goroutines when /avatar/:hash requests time out",
"x_generator": {
"engine": "cvelib 1.8.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "57da9224-a3e2-4646-9d0e-c4dc2e05e7da",
"assignerShortName": "GRAFANA",
"cveId": "CVE-2026-21720",
"datePublished": "2026-01-27T09:07:04.758Z",
"dateReserved": "2026-01-05T09:26:06.214Z",
"dateUpdated": "2026-08-27T17:22:47.419Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"vulnrichment": {
"containers": "{\"adp\": [{\"title\": \"grafana: Grafana: Denial of Service via resource exhaustion from avatar requests\", \"metrics\": [{\"other\": {\"type\": \"Red Hat severity rating\", \"content\": {\"value\": \"Important\", \"namespace\": \"https://access.redhat.com/security/updates/classification/\"}}}, {\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}], \"affected\": [{\"cpes\": [\"cpe:/a:redhat:ceph_storage:7\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Ceph Storage 7\", \"packageName\": \"rhceph/grafana-rhel9\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"unaffected\"}, {\"cpes\": [\"cpe:/a:redhat:ceph_storage:8\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Ceph Storage 8\", \"packageName\": \"rhceph/grafana-rhel9\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"unaffected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:10\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 10\", \"packageName\": \"grafana\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"unaffected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:8\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 8\", \"packageName\": \"grafana\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"unaffected\"}, {\"cpes\": [\"cpe:/o:redhat:enterprise_linux:9\"], \"vendor\": \"Red Hat\", \"product\": \"Red Hat Enterprise Linux 9\", \"packageName\": \"grafana\", \"collectionURL\": \"https://access.redhat.com/downloads/content/package-browser/\", \"defaultStatus\": \"unaffected\"}], \"timeline\": [{\"lang\": \"en\", \"time\": \"2026-01-27T10:01:10.677Z\", \"value\": \"Reported to Red Hat.\"}, {\"lang\": \"en\", \"time\": \"2026-01-27T09:07:04.758Z\", \"value\": \"Made public.\"}], \"x_adpType\": \"supplier\", \"datePublic\": \"2026-01-27T09:07:04.758Z\", \"references\": [{\"url\": \"https://access.redhat.com/security/cve/CVE-2026-21720\", \"tags\": [\"vdb-entry\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=2433226\", \"name\": \"RHBZ#2433226\", \"tags\": [\"issue-tracking\", \"x_refsource_REDHAT\"]}, {\"url\": \"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-21720.json\", \"tags\": [\"x_sadp-csaf-vex\"]}], \"x_generator\": {\"engine\": \"sadp-cli 1.0.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"A flaw was found in Grafana. A remote attacker can exploit this vulnerability by sending a sustained volume of uncached /avatar/:hash requests. This action causes the system to create and block goroutines, which are lightweight concurrent functions, leading to a continuous increase in memory usage. Over time, this resource exhaustion can cause Grafana to crash, resulting in a Denial of Service (DoS).\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-772\", \"description\": \"Missing Release of Resource after Effective Lifetime\"}]}], \"providerMetadata\": {\"orgId\": \"0b0ca135-0b70-47e7-9f44-1890c2a1c46c\", \"shortName\": \"redhat-SADP\", \"dateUpdated\": \"2026-07-15T01:19:55.276Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-21720\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-01-27T14:28:02.795937Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-400\", \"description\": \"CWE-400 Uncontrolled Resource Consumption\"}]}, {\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-703\", \"description\": \"CWE-703 Improper Check or Handling of Exceptional Conditions\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-01-27T14:27:05.963Z\"}}], \"cna\": {\"title\": \"Unauthenticated DoS: avatar cache leaks goroutines when /avatar/:hash requests time out\", \"source\": {\"discovery\": \"BUG_BOUNTY\"}, \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 7.5, \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\"}}], \"affected\": [{\"vendor\": \"Grafana\", \"product\": \"grafana/grafana-enterprise\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"11.6.9\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}, {\"vendor\": \"Grafana\", \"product\": \"grafana/grafana-enterprise\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"12.0.8\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}, {\"vendor\": \"Grafana\", \"product\": \"grafana/grafana-enterprise\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"12.1.5\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}, {\"vendor\": \"Grafana\", \"product\": \"grafana/grafana\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"11.6.9\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}, {\"vendor\": \"Grafana\", \"product\": \"grafana/grafana\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"12.0.8\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}, {\"vendor\": \"Grafana\", \"product\": \"grafana/grafana\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"12.1.5\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}, {\"vendor\": \"Grafana\", \"product\": \"grafana/grafana-enterprise\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"12.2.3\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}, {\"vendor\": \"Grafana\", \"product\": \"grafana/grafana\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"12.2.3\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}, {\"vendor\": \"Grafana\", \"product\": \"grafana/grafana-enterprise\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"12.3.1\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}, {\"vendor\": \"Grafana\", \"product\": \"grafana/grafana\", \"versions\": [{\"status\": \"affected\", \"version\": \"3.0.0\", \"lessThan\": \"12.3.1\", \"versionType\": \"semver\"}], \"defaultStatus\": \"unaffected\"}], \"datePublic\": \"2026-01-27T09:03:09.893Z\", \"references\": [{\"url\": \"https://grafana.com/security/security-advisories/cve-2026-21720\", \"tags\": [\"vendor-advisory\"]}], \"x_generator\": {\"engine\": \"cvelib 1.8.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"Every uncached /avatar/:hash request spawns a goroutine that refreshes the Gravatar image. If the refresh sits in the 10-slot worker queue longer than three seconds, the handler times out and stops listening for the result, so that goroutine blocks forever trying to send on an unbuffered channel. Sustained traffic with random hashes keeps tripping this timeout, so goroutine count grows linearly, eventually exhausting memory and causing Grafana to crash on some systems.\", \"supportingMedia\": [{\"type\": \"text/markdown\", \"value\": \"Every uncached /avatar/:hash request spawns a goroutine that refreshes the Gravatar image. If the refresh sits in the 10-slot worker queue longer than three seconds, the handler times out and stops listening for the result, so that goroutine blocks forever trying to send on an unbuffered channel. Sustained traffic with random hashes keeps tripping this timeout, so goroutine count grows linearly, eventually exhausting memory and causing Grafana to crash on some systems.\"}]}], \"providerMetadata\": {\"orgId\": \"57da9224-a3e2-4646-9d0e-c4dc2e05e7da\", \"shortName\": \"GRAFANA\", \"dateUpdated\": \"2026-08-27T17:22:47.419Z\"}}}",
"cveMetadata": "{\"cveId\": \"CVE-2026-21720\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-27T17:22:47.419Z\", \"dateReserved\": \"2026-01-05T09:26:06.214Z\", \"assignerOrgId\": \"57da9224-a3e2-4646-9d0e-c4dc2e05e7da\", \"datePublished\": \"2026-01-27T09:07:04.758Z\", \"assignerShortName\": \"GRAFANA\"}",
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…