How severe is CVE-2021-32707?

CVE-2021-32707 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-32707 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-32707?

CVE-2021-32707 affects Nextcloud Mail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-32707?

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

When was CVE-2021-32707 published?

CVE-2021-32707 was published on 2021-07-12 and last updated on 2026-06-17.

CVE-2021-32707

CVE-2021-32707 is a medium-severity vulnerability in Nextcloud Mail with a CVSS 3.x base score of 4.3. 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-20.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.0
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Nextcloud Mail
Published: 2021-07-12
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-32707?: CVE-2021-32707 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-32707 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-32707?: CVE-2021-32707 affects Nextcloud Mail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-32707?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-32707 published?: CVE-2021-32707 was published on 2021-07-12 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nextcloud:mail:*:*:*:*:*:*:*:*

More vulnerabilities in Nextcloud Mail

CVE-2021-32652 — High (CVSS 8.8): Nextcloud Mail is a mail app for the Nextcloud platform. A missing permission check in Nextcloud Mail before 1.4.3 and…
CVE-2022-31132 — High (CVSS 8.3): Nextcloud Mail is an email application for the nextcloud personal cloud product. Affected versions shipped with a CSS…
CVE-2024-52508 — High (CVSS 8.2): Nextcloud Mail is the mail app for Nextcloud, a self-hosted productivity platform. When a user is trying to set up a…
CVE-2020-8156 — High (CVSS 7.0): A missing verification of the TLS host in Nextcloud Mail 1.1.3 allowed a man in the middle attack.
CVE-2023-23943 — Medium (CVSS 5.0): Nextcloud mail is an email app for the nextcloud home server platform. In affected versions the SMTP, IMAP and Sieve…
CVE-2023-45660 — Medium (CVSS 4.3): Nextcloud mail is an email app for the Nextcloud home server platform. In affected versions a missing check of origin,…

All CVEs affecting Nextcloud Mail →

Other CWE-20 (Improper Input Validation) vulnerabilities

CVE-2026-48316 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48281 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48277 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48055 — Critical (CVSS 10.0): Streambert is a cross-platform Electron Desktop App to stream and download any video media. In versions 2.4.0 and…
CVE-2026-34910 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS…
CVE-2026-33587 — Critical (CVSS 10.0): Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and…

Browse all CWE-20 (Improper Input Validation) vulnerabilities →