How severe is CVE-2025-66556?

CVE-2025-66556 has a CVSS 3.x base score of 3.5, rated low severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2025-66556 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-66556?

CVE-2025-66556 affects Nextcloud Talk. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-66556?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-66556 have an EU (EUVD) identifier?

Yes. CVE-2025-66556 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201458.

When was CVE-2025-66556 published?

CVE-2025-66556 was published on 2025-12-05 and last updated on 2026-06-17.

CVE-2025-66556

CVE-2025-66556 is a low-severity vulnerability in Nextcloud Talk with a CVSS 3.x base score of 3.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-639.

Key facts

Severity: Low (CVSS 3.x base score 3.5)
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-201458
Weakness: CWE-639
Affected product: Nextcloud Talk
Published: 2025-12-05
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2025-66556?: 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.
How severe is CVE-2025-66556?: CVE-2025-66556 has a CVSS 3.x base score of 3.5, rated low severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2025-66556 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66556?: CVE-2025-66556 affects Nextcloud Talk. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-66556?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-66556 have an EU (EUVD) identifier?: Yes. CVE-2025-66556 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201458.
When was CVE-2025-66556 published?: CVE-2025-66556 was published on 2025-12-05 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nextcloud:talk:*:*:*:*:*:*:*:*

More vulnerabilities in Nextcloud Talk

CVE-2020-8180 — Critical (CVSS 9.9): A too lax check in Nextcloud Talk 6.0.4, 7.0.2 and 8.0.7 allowed a code injection when a not correctly sanitized talk…
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CVE-2023-39957 — High (CVSS 7.8): Nextcloud Talk Android allows users to place video and audio calls through Nextcloud on Android. Prior to version…
CVE-2021-32676 — Medium (CVSS 6.5): Nextcloud Talk is a fully on-premises audio/video and chat communication service. Password protected shared chats in…
CVE-2021-39222 — Medium (CVSS 6.4): Nextcloud is an open-source, self-hosted productivity platform. The Nextcloud Talk application was vulnerable to a…
CVE-2018-3781 — Medium (CVSS 5.4): A missing sanitization of search results for an autocomplete field in NextCloud Talk <3.2.5 could lead to a stored XSS…

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