CVE-2023-35927

Nextcloud system addressbooks can be modified by malicious trusted server

HIGH

8.1

CVSS Score

Published: June 23, 2023 at 08:53 PM UTC

Updated: June 17, 2026 at 06:05 AM UTC

1 product affected across 1 vendorNextcloud/server

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Severity

HIGH8.1

Exploit prediction

EPSS 0.8%

SSVC

No known exploit

Description

NextCloud Server and NextCloud Enterprise Server provide file storage for Nextcloud, a self-hosted productivity platform. In NextCloud Server versions 25.0.0 until 25.0.7 and 26.0.0 until 26.0.2 and Nextcloud Enterprise Server versions 21.0.0 until 21.0.9.12, 22.0.0 until 22.2.10.12, 23.0.0 until 23.0.12.7, 24.0.0 until 24.0.12.2, 25.0.0 until 25.0.7, and 26.0.0 until 26.0.2, when two server are registered as trusted servers for each other and successfully exchanged the share secrets, the malicious server could modify or delete VCards in the system addressbook on the origin server. This would impact the available and shown information in certain places, such as the user search and avatar menu. If a manipulated user modifies their own data in the personal settings the entry is fixed again. Nextcloud Server n 25.0.7 and 26.0.2 and Nextcloud Enterprise Server 21.0.9.12, 22.2.10.12, 23.0.12.7, 24.0.12.2, 25.0.7, and 26.0.2 contain a patch for this issue. A workaround is available. Remove all trusted servers in the "Administration" > "Sharing" settings `…/index.php/settings/admin/sharing`. Afterwards, trigger a recreation of the local system addressbook with the following `occ dav:sync-system-addressbook`.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Nextcloud/server · Nextcloudnextcloud-app

95%

16.0.0 ≤ v < 19.0.13.920.0.0 ≤ v < 20.0.14.1421.0.0 ≤ v < 21.0.9.1222.0.0 ≤ v < 22.2.10.1223.0.0 ≤ v < 23.0.12.724.0.0 ≤ v < 24.0.12.225.0.0 ≤ v < 25.0.726.0.0 ≤ v < 26.0.2

Affected range stops below 19.0.13.9, so it looks safe — our inference, not a vendor statement

Affected range stops below 20.0.14.14, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.0.9.12, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.2.10.12, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.0.12.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 24.0.12.2, so it looks safe — our inference, not a vendor statement

Affected range stops below 25.0.7, so it looks safe — our inference, not a vendor statement

Affected range stops below 26.0.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-h7f7-535f-7q87

References (3)

x_refsource_CONFIRMVendor Advisory

Source: [email protected]

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-h7f7-535f-7q87

x_refsource_MISCIssue Tracking

Source: [email protected]

https://github.com/nextcloud/server/pull/38247

x_refsource_MISCPermissions Required

Source: [email protected]

https://hackerone.com/reports/1976754

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.1HIGH[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: LOW
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: HIGH
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-284NVD-CWE-noinfo

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