CVE-2021-38507
Severity CVSS v4.0:
Pending analysis
Type:
Unavailable / Other
Publication date:
08/12/2021
Last modified:
09/12/2022
Description
The Opportunistic Encryption feature of HTTP2 (RFC 8164) allows a connection to be transparently upgraded to TLS while retaining the visual properties of an HTTP connection, including being same-origin with unencrypted connections on port 80. However, if a second encrypted port on the same IP address (e.g. port 8443) did not opt-in to opportunistic encryption; a network attacker could forward a connection from the browser to port 443 to port 8443, causing the browser to treat the content of port 8443 as same-origin with HTTP. This was resolved by disabling the Opportunistic Encryption feature, which had low usage. This vulnerability affects Firefox
Impact
Base Score 3.x
6.50
Severity 3.x
MEDIUM
Base Score 2.0
4.30
Severity 2.0
MEDIUM
Vulnerable products and versions
| CPE | From | Up to |
|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* | 94.0 (excluding) | |
| cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* | 91.3.0 (excluding) | |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | 91.3.0 (excluding) | |
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | ||
| cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* | ||
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* |
To consult the complete list of CPE names with products and versions, see this page
References to Advisories, Solutions, and Tools
- https://bugzilla.mozilla.org/show_bug.cgi?id=1730935
- https://lists.debian.org/debian-lts-announce/2021/12/msg00030.html
- https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html
- https://security.gentoo.org/glsa/202202-03
- https://security.gentoo.org/glsa/202208-14
- https://www.debian.org/security/2021/dsa-5026
- https://www.debian.org/security/2022/dsa-5034
- https://www.mozilla.org/security/advisories/mfsa2021-48/
- https://www.mozilla.org/security/advisories/mfsa2021-49/
- https://www.mozilla.org/security/advisories/mfsa2021-50/