CVE-2021-32707: nextcloud mail Improper Input Validation
Vulnerability summary
CVE-2021-32707 is a medium (CVSS 4.3) Improper Input Validation vulnerability in nextcloud mail. EPSS estimates a 1.15% chance of exploitation in the next 30 days, higher than 66.2% of scored vulnerabilities. 1 public exploit is recorded.
Timeline
- 12-07-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 2 sources · 2 versions- NVDNIST4.3MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
EPSS trend
Probability
1.15%
Chance of exploitation in the next 30 days
Percentile
66%
Versus all other CVEs
30-day change
0.00 pp
From 1.15% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (hackerone.com)
Maturity: unknown
Weaknesses
CWE · root cause- CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- CWE-200Exposure of Sensitive Information to an Unauthorized ActorThe product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
Affected systems
Nextcloud2 products
- mail< 1.9.6
- security-advisories< 1.9.6
1 vendor · 2 products
References
3 links- github.com/nextcloud/security-advisories/security/advisories/GHSA-xxp4-44xc-8crhX Refsource CONFIRMThird Party Advisory