CVE-2017-7821

A vulnerability where WebExtensions can download and attempt to open a file of some non-executable file types.

Published 11 Jun 2018Modified 17 Jun 2026CWE 732

In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.

Severity by source

NVD9.8CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Trivy's own label is CRITICAL. Rated critical by NVD. Rated lower by Ubuntu (medium).

Description

A vulnerability where WebExtensions can download and attempt to open a file of some non-executable file types. This can be triggered without specific user interaction for the file download and open actions. This could be used to trigger known vulnerabilities in the programs that handle those document types. This vulnerability affects Firefox < 56.

Affected packages and fixed versions

Source	Package	Fixed in
ubuntu 14.04	firefox	56.0+build6-0ubuntu0.14.04.1
ubuntu 16.04	firefox	56.0+build6-0ubuntu0.16.04.1
ubuntu 17.04	firefox	56.0+build6-0ubuntu0.17.04.1
ubuntu 17.10	firefox	56.0+build6-0ubuntu1
ubuntu 18.04	firefox	56.0+build6-0ubuntu1

References

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Vulnerability data compiled from the Trivy vulnerability database (trivy-db, Aqua Security, Apache License 2.0), which aggregates third-party advisories. CVE records are published by The MITRE Corporation under the CVE Terms of Use; CVE is a trademark of MITRE. This product uses data from the NVD API but is not endorsed or certified by the NVD. Severity, titles and advisory data from the GitHub Advisory Database (CC BY 4.0), Red Hat security data (CC BY 4.0) and the other sources linked on each entry. Entries may be summarised or re-formatted; the linked original is the authoritative record.