What is CVE-2021-32707?

CVE-2021-32707 is a medium-severity vulnerability in Nextcloud Mail, classified under Improper Input Validation. CVSS score: 4.3/10. Published 2021-07-12.

How severe is CVE-2021-32707?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Information disclosure in Nextcloud Mail

CVE-2021-32707

Nextcloud Mail is a mail app for Nextcloud. In versions prior to 1.9.6, the Nextcloud Mail application does not, by default, render images in emails to not leak the read state. The privacy filter failed to filter images with a `background-image` CSS attribute. Note that the images were still passed through the Nextcloud image proxy, and thus there was no IP leakage. The issue was patched in version 1.9.6 and 1.10.0. No workarounds are known to exist.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

Published 2021-07-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.011 (65.5th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 65th percentile — 65.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Nextcloud Mail
Nextcloud Security-Advisories — versions < 1.9.6

Weakness classification (CWE)

References

github.com/nextcloud/security-advisories/security/advisories/GHSA-xxp4-44xc-8crh (Third Party Advisory)
github.com/nextcloud/mail/pull/5189 (Patch, Third Party Advisory)
hackerone.com/reports/1215251 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-32707?: CVE-2021-32707 is a medium-severity vulnerability in Nextcloud Mail, classified under Improper Input Validation. CVSS score: 4.3/10. Published 2021-07-12.
How severe is CVE-2021-32707?: Medium severity. CVSS v3 base score is 4.3 out of 10.