4.3

CVE-2025-66556: nextcloud security-advisories

CVSS: 4.3v3.1MediumAnalyzed
Published 05-12-2025Last modified 05-12-2025
Open JSON

Vulnerability summary

CVE-2025-66556 is a medium (CVSS 4.3) vulnerability in nextcloud security-advisories. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.8% of scored vulnerabilities.

Overall risk
17/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (NVD)
EPSS score
0.25%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 05-12-2025
    PublishedVulnerability first disclosed.
  2. 05-12-2025
    Last modifiedVulnerability information updated.

Description

Nextcloud talk is a video & audio conferencing app for Nextcloud. Prior to 20.1.8 and 21.1.2, a participant with chat permissions was able to delete poll drafts of other participants within the conversation based on their numeric ID. This vulnerability is fixed in 20.1.8 and 21.1.2.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.25%

Chance of exploitation in the next 30 days

Percentile

16%

Versus all other CVEs

30-day change

0.00 pp

From 0.25% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.25%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Nextcloud2 products

1 vendor · 2 products

References

4 links