|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 < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.|
|Source||CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)|
|References||DLA-2863-1, DLA-2874-1, DSA-5026-1, DSA-5034-1|
Vulnerable and fixed packages
The table below lists information on source packages.
|bookworm, bookworm (security)||115.5.0esr-1~deb12u1||fixed|
|bookworm, bookworm (security)||1:115.5.0-1~deb12u1||fixed|
The information below is based on the following data on fixed versions.