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CWE

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CVE-2025-66514

Published: Dec 5, 2025

Modified: Dec 8, 2025

PUBLISHED

CVSS v3.1

3.5

LOW

Description

Nextcloud Mail is the mail app for Nextcloud, a self-hosted productivity platform. Prior to 5.5.3, a stored HTML injection in the Mail app's message list allowed an authenticated user to inject HTML into the email subjects. Javascript was correctly blocked by the content security policy of the Nextcloud Server code.

Vendor	Product	Versions
nextcloud	security-advisories	affected `>= 5.2.0-beta.1, < 5.5.3`

Weaknesses (CWE)

CVSS v3.1 Details

CVSS v3.1 Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-v394-8gpc-6fv5

x_refsource_CONFIRM

https://github.com/nextcloud/mail/pull/11740

x_refsource_MISC

https://github.com/nextcloud/mail/commit/c64fcc3b79e0c089b5e1d2e04a07bfa740b2ac09

x_refsource_MISC

https://hackerone.com/reports/3357036

x_refsource_MISC

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