CVE-2026-45281

highpriority · track · 0EPSS 0.003 · 21 %ileDEEUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.28% (21st) EPSS
CVSS 8.1 · high
Is it mine?
61 products
Check your exposure
Who says so?
4 sources
cnnvd · enisa_euvd · osv · cert_bund

EPSS · scored 2026-10-27

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

01

cvss

Technical severity, 0–10. One row per scoring source.

8.1
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.18.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Nsecondary · ENISA EU
v3.18.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Nsecondary · security-advisories@github.comexploitability 2.8 · impact 5.2
v3.17.4highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-639US
04

affected products (61)

Products and version ranges known to be affected.

showing 20 of 61
05

advisories (2)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-1471Nextcloud: Mehrere SchwachstellenDeutsch2026-05-11csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen im Nextcloud Server und verschiedenen Apps ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um Informationen offenzulegen, und um Dateien zu manipulieren.

  • BIT-nextcloud-2026-45281Nextcloud: Cross-Account Calendar Takeover via Unauthorized Group-Member-Set Update2026-07-12vendor · osvUS

    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

06

also known as (3)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdosvcert_bundNVDCVE.orgMITRE
published 2026-06-01modified 2026-07-22
08

references (11)

External citations — patches, advisories, analysis.

scry

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