CVE-2021-38507

CVE Details

Release Date:

2021-12-08

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.

See more information about CVE-2021-38507 from MITRE CVE dictionary and NIST NVD

CVSS v3.0 metrics

NOTE: The following CVSS v3.0 metrics and score provided are preliminary and subject to review.

Base Score:	6.5	Base Metrics:	AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Access Vector:	Network	Attack Complexity:	Low
Privileges Required:	None	User Interaction:	Required
Scope:	Unchanged	Confidentiality Impact:	None
Integrity Impact:	High	Availability Impact:	None

Errata information

Platform	Errata	Release Date
Oracle Linux version 7 (firefox)	ELSA-2021-4116	2021-11-04
Oracle Linux version 7 (thunderbird)	ELSA-2021-4134	2021-11-05
Oracle Linux version 8 (firefox)	ELSA-2021-4123	2021-11-04
Oracle Linux version 8 (thunderbird)	ELSA-2021-4130	2021-11-05

This page is generated automatically and has not been checked for errors or omissions. For clarification or corrections please contact the Oracle Linux ULN team