FKIE_CVE-2026-45281
Vulnerability from fkie_nvd - Published: 2026-06-01 19:16 - Updated: 2026-07-22 07:10
Severity
Summary
Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, with the knowledge of other users’ principal URL an attacker could possibly send a request to gain full access to their calendar. Therefore, the attacker must be an authenticated user. This is because of improper authorization controls in the backend of the calendar. If the attacker had access to the calendar, they would be able to view and modify it. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended that the Nextcloud Enterprise Server is upgraded to 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9, 29.0.16.16, 28.0.14.17, 27.1.11.26, 26.0.13.26, 25.0.13.29, 24.0.12.34, 23.0.12.35, 22.2.10.39, or 21.0.9.23
References
| URL | Tags | ||
|---|---|---|---|
| security-advisories@github.com | https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hrrv-mp25-26vv | Mitigation, Vendor Advisory | |
| security-advisories@github.com | https://github.com/nextcloud/server/pull/59962 | Issue Tracking, Patch | |
| security-advisories@github.com | https://hackerone.com/reports/3545964 | Permissions Required |
Impacted products
{
"affected": [
{
"affectedData": [
{
"product": "security-advisories",
"vendor": "nextcloud",
"versions": [
{
"status": "affected",
"version": "\u003e= 32.0.0, \u003c 32.0.9"
},
{
"status": "affected",
"version": "\u003e= 33.0.0, \u003c 33.0.3"
}
]
}
],
"source": "security-advisories@github.com"
}
],
"configurations": [
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"versionEndExcluding": "32.0.9",
"versionStartIncluding": "32.0.0",
"vulnerable": true
},
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"matchCriteriaId": "9B2B8E97-72E8-48AE-85F0-9FB5CE692F14",
"versionEndExcluding": "33.0.3",
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}
],
"negate": false,
"operator": "OR"
}
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],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, with the knowledge of other users\u2019 principal URL an attacker could possibly send a request to gain full access to their calendar. Therefore, the attacker must be an authenticated user. This is because of improper authorization controls in the backend of the calendar. If the attacker had access to the calendar, they would be able to view and modify it. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended that the Nextcloud Enterprise Server is upgraded to 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9, 29.0.16.16, 28.0.14.17, 27.1.11.26, 26.0.13.26, 25.0.13.29, 24.0.12.34, 23.0.12.35, 22.2.10.39, or 21.0.9.23"
},
{
"lang": "es",
"value": "Nextcloud es una plataforma de colaboraci\u00f3n de contenido de c\u00f3digo abierto. En Nextcloud Server desde las versiones 32.0.0 hasta antes de la 32.0.9, y 33.0.0 hasta antes de la 33.0.3, con el conocimiento de la URL principal de otros usuarios, un atacante podr\u00eda posiblemente enviar una solicitud para obtener acceso completo a su calendario. Por lo tanto, el atacante debe ser un usuario autenticado. Esto se debe a controles de autorizaci\u00f3n inadecuados en el backend del calendario. Si el atacante tuviera acceso al calendario, podr\u00eda verlo y modificarlo. Se recomienda que el Nextcloud Server se actualice a 33.0.3 o 32.0.9. Se recomienda que el Nextcloud Enterprise Server se actualice a 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9, 29.0.16.16, 28.0.14.17, 27.1.11.26, 26.0.13.26, 25.0.13.29, 24.0.12.34, 23.0.12.35, 22.2.10.39, o 21.0.9.23."
}
],
"id": "CVE-2026-45281",
"lastModified": "2026-07-22T07:10:00.107",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 8.1,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 5.2,
"source": "security-advisories@github.com",
"type": "Secondary"
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"id": "CVE-2026-45281",
"options": [
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{
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{
"technicalImpact": "total"
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],
"role": "CISA Coordinator",
"timestamp": "2026-06-01T19:22:37.089766Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-06-01T19:16:50.193",
"references": [
{
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"tags": [
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],
"url": "https://github.com/nextcloud/security-advisories/security/advisories/GHSA-hrrv-mp25-26vv"
},
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"url": "https://hackerone.com/reports/3545964"
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"sourceIdentifier": "security-advisories@github.com",
"vulnStatus": "Analyzed",
"weaknesses": [
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"description": [
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"value": "CWE-639"
}
],
"source": "security-advisories@github.com",
"type": "Secondary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
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