What is CVE-2018-3781?

CVE-2018-3781 is a medium-severity vulnerability in Nextcloud Nextcloud/talk, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2018-08-13.

How severe is CVE-2018-3781?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Nextcloud Nextcloud/talk

CVE-2018-3781

A missing sanitization of search results for an autocomplete field in NextCloud Talk <3.2.5 could lead to a stored XSS requiring user-interaction. The missing sanitization only affected user names, hence malicious search results could only be crafted by authenticated users.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2018-08-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (52.9th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 52.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Nextcloud Nextcloud/talk — versions >=3.2.5
Nextcloud Talk

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

hackerone.com/reports/383117 (Third Party Advisory)
nextcloud.com/security/advisory/ (Vendor Advisory)

Frequently asked questions

What is CVE-2018-3781?: CVE-2018-3781 is a medium-severity vulnerability in Nextcloud Nextcloud/talk, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2018-08-13.
How severe is CVE-2018-3781?: Medium severity. CVSS v3 base score is 5.4 out of 10.