CVE-2025-66554

mediumpriority · track · 22EPSS 0.003 · 16 %ileDEEURUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.25% (16th) EPSS
CVSS 5.4 · medium
Is it mine?
16 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-28

Contacts app for Nextcloud easily syncs contacts from various devices with your Nextcloud and allows editing. Prior to 5.5.4, 6.0.6, and 7.2.5, a malicious user was able to modify their organisation and title field to load additional CSS files. Javascript and other options were correctly blocked by the content security policy of the Nextcloud Server code. This vulnerability is fixed in 5.5.4, 6.0.6, and 7.2.5.

01

cvss

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

5.4
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 3.5–5.4

v3.15.4mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 2.3 · impact 2.7
v3.15.4mediumAV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:Nsecondary · FSTEC (BDU) RU
v3.13.5lowCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:Nsecondary · ENISA EU
v3.13.5lowCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:Nsecondary · security-advisories@github.comexploitability 2.1 · impact 1.4
v3.15mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

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

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-79USCWE-79US
04

affected products (16)

Products and version ranges known to be affected.

05

advisories (1)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2025-2757Nextcloud (Contacts, Talk, Deck und Twofactor WebAuthn): Mehrere SchwachstellenDeutsch2025-12-07csaf · cert_bundDE

    Ein Angreifer kann mehrere Schwachstellen in Nextcloud ausnutzen, um einen Cross-Site Scripting Angriff durchzuführen, um Dateien zu manipulieren, und um Sicherheitsvorkehrungen zu umgehen.

06

also known as (3)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducert_bundnvdNVDCVE.orgMITRE
published 2025-12-05modified 2026-06-17
08

references (13)

External citations — patches, advisories, analysis.

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