Vulnerability · Published Oct 25, 2021 · Assigned by GitHub_M

CVE-2021-39220Bypass of image blocking in Nextcloud Mail

Low 3.5

In plain English

A low-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 0.9% (higher than 60% of all known vulnerabilities).

Severity (CVSS 3.1)3.5Low

Exploit odds (30 days)0.9%top 39.9% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official description

Nextcloud is an open-source, self-hosted productivity platform The Nextcloud Mail application prior to versions 1.10.4 and 1.11.0 does by default not render images in emails to not leak the read state or user IP. The privacy filter failed to filter images with a relative protocol. It is recommended that the Nextcloud Mail application is upgraded to 1.10.4 or 1.11.0. There are no known workarounds aside from upgrading.

Affected products (as reported)

Vendor	Product	Versions
nextcloud	security-advisories	< 1.10.4, < 1.11.0

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

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-6q9v-wm8r-rcv5 x_refsource_CONFIRM
https://github.com/nextcloud/mail/pull/5470 x_refsource_MISC
https://hackerone.com/reports/1308147 x_refsource_MISC