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CVE-2021-38507

Publication date 3 November 2021

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

6.5 · Medium

Score breakdown

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.

Read the notes from the security team

Status

Package Ubuntu Release Status
firefox 24.04 LTS noble
Fixed 94.0+build3-0ubuntu1
23.10 mantic
Fixed 94.0+build3-0ubuntu1
23.04 lunar
Fixed 94.0+build3-0ubuntu1
22.10 kinetic
Fixed 94.0+build3-0ubuntu1
22.04 LTS jammy
Fixed 94.0+build3-0ubuntu1
21.10 impish
Fixed 94.0+build3-0ubuntu0.21.10.1
21.04 hirsute
Fixed 94.0+build3-0ubuntu0.21.04.1
20.04 LTS focal
Fixed 94.0+build3-0ubuntu0.20.04.1
18.04 LTS bionic
Fixed 94.0+build3-0ubuntu0.18.04.1
16.04 LTS xenial Ignored end of standard support, was needed
14.04 LTS trusty Not in release
mozjs38 24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Not in release
22.10 kinetic Not in release
22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.04 LTS focal Not in release
18.04 LTS bionic Ignored
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
mozjs52 24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Not in release
22.10 kinetic Not in release
22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.04 LTS focal Ignored
18.04 LTS bionic Ignored
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
mozjs68 24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Not in release
22.10 kinetic Not in release
22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.04 LTS focal Ignored
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
mozjs78 24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Ignored end of life, was needs-triage
22.10 kinetic Ignored end of life, was needs-triage
22.04 LTS jammy Ignored
21.10 impish Ignored end of life
21.04 hirsute Ignored end of life
20.04 LTS focal Not in release
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
thunderbird 24.04 LTS noble
Fixed 1:91.3.1+build1-0ubuntu1
23.10 mantic
Fixed 1:91.3.1+build1-0ubuntu1
23.04 lunar
Fixed 1:91.3.1+build1-0ubuntu1
22.10 kinetic
Fixed 1:91.3.1+build1-0ubuntu1
22.04 LTS jammy
Fixed 1:91.3.1+build1-0ubuntu1
21.10 impish
Fixed 1:91.3.1+build1-0ubuntu0.21.10.1
21.04 hirsute Ignored end of life
20.04 LTS focal
Fixed 1:91.5.0+build1-0ubuntu0.20.04.1
18.04 LTS bionic
Fixed 1:91.5.0+build1-0ubuntu0.18.04.1
16.04 LTS xenial Ignored end of standard support, was needed
14.04 LTS trusty Not in release

Notes

tyhicks

mozjs contains a copy of the SpiderMonkey JavaScript engine

Severity score breakdown

Parameter Value
Base score 6.5 · Medium
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Scope Unchanged
Confidentiality None
Integrity impact High
Availability impact None
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

References

Related Ubuntu Security Notices (USN)

    • USN-5131-1
    • Firefox vulnerabilities
    • 3 November 2021
    • USN-5152-1
    • Thunderbird vulnerabilities
    • 18 November 2021
    • USN-5248-1
    • Thunderbird vulnerabilities
    • 21 January 2022

Other references