CVE-2025-66514 json
Nextcloud Mail stored HTML injection in subject text
published 2025-12-05 11 mo ago modified 2026-10-15 24 d ago also EUVD-2025-201464
- cvss
- 3.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 19%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- nextcloud mail 5.5.3
- nextcloud nextcloud_mail 5.5.3
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 11 mo ago
Exploit prediction
0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 3.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N |
| NVD | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
Affected products
- nextcloud security-advisories
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/nextcloud/mail/pull/11740
issue-tracking, patch
-
github.com
/nextcloud/mail/commit/c64fcc3b79e0c089b5e1d2e04a07bfa740b2ac09
patch
-
github.com
/nextcloud/security-advisories/security/advisories/GHSA-v394-8gpc-6fv5
patch, vendor-advisory
-
hackerone.com
/reports/3357036
permissions-required, vendor-advisory
Sources
- CVE List CVE-2025-66514
- NVD CVE-2025-66514
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.