Vulnerability · Published Jul 12, 2021 · Assigned by GitHub_M

CVE-2021-32707Bypass of image blocking in Nextcloud Mail

Medium 4.3

In plain English

A medium-severity improper input validation in security-advisories from nextcloud. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 67% of all known vulnerabilities).

Severity (CVSS 3.1)4.3Medium

Exploit odds (30 days)1.1%top 33.1% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
nextcloud	security-advisories	< 1.9.6

Weakness: CWE-20, CWE-200 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-xxp4-44xc-8crh x_refsource_CONFIRM
https://github.com/nextcloud/mail/pull/5189 x_refsource_MISC
https://hackerone.com/reports/1215251 x_refsource_MISC