CVE-2025-66514
Nextcloud Mail stored HTML injection in subject text
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.
INFO
Published Date :
Dec. 5, 2025, 6:15 p.m.
Last Modified :
Dec. 5, 2025, 6:15 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2025-66514
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | LOW | [email protected] |
Solution
- Update the Nextcloud Mail app to 5.5.3.
- Apply any available security patches.
- Review and enforce content security policies.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-66514.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-66514 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-66514
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-66514 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-66514 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Dec. 05, 2025
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N Added CWE CWE-79 Added Reference https://github.com/nextcloud/mail/commit/c64fcc3b79e0c089b5e1d2e04a07bfa740b2ac09 Added Reference https://github.com/nextcloud/mail/pull/11740 Added Reference https://github.com/nextcloud/security-advisories/security/advisories/GHSA-v394-8gpc-6fv5 Added Reference https://hackerone.com/reports/3357036