CVE-2025-66546

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.14% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 3.5% of scored records. A rank, not a probability.

NVD base score

3.3 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Analyzed. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2025-12-05 16:49Z9 MO AGO

Last updated

2025-12-05 18:32Z9 MO AGO

Reserved

2025-12-04

Assigning CNA

GitHub_M

Record state

PUBLISHED

Severity

Low (CVSS 3.3)

CNA CVSS vector

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

Weaknesses

• CWE-639Authorization Bypass Through User-Controlled KeyBase

Data version

5.2

Document digest

294fe60d3d2fecd9c0f4fc547de3089d281e72c199214797e26e3bec778e9452

• github.comhttps://github.com/nextcloud/security-advisories/security/advisories/GHSA-7x2j-2674-fj95x_refsource_CONFIRM
• github.comhttps://github.com/nextcloud/calendar/pull/7537x_refsource_MISC
• github.comhttps://github.com/nextcloud/calendar/commit/f41650c3681fc4a4130eb883f5c0899c011326b3x_refsource_MISC
• hackerone.comhttps://hackerone.com/reports/3275810x_refsource_MISC