CVE-2021-38507

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.
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*

Configuration 2 (hide)

OR 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:*:*:*:*:*:*:*

History

09 Dec 2022, 15:54

Type Values Removed Values Added
References (GENTOO) https://security.gentoo.org/glsa/202208-14 - (GENTOO) https://security.gentoo.org/glsa/202208-14 - Third Party Advisory

10 Aug 2022, 20:15

Type Values Removed Values Added
References
  • (GENTOO) https://security.gentoo.org/glsa/202208-14 -

16 Mar 2022, 17:19

Type Values Removed Values Added
References (GENTOO) https://security.gentoo.org/glsa/202202-03 - (GENTOO) https://security.gentoo.org/glsa/202202-03 - Third Party Advisory
References (DEBIAN) https://www.debian.org/security/2022/dsa-5034 - (DEBIAN) https://www.debian.org/security/2022/dsa-5034 - Third Party Advisory
References (MLIST) https://lists.debian.org/debian-lts-announce/2021/12/msg00030.html - (MLIST) https://lists.debian.org/debian-lts-announce/2021/12/msg00030.html - Mailing List, Third Party Advisory
References (MLIST) https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html - (MLIST) https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html - Mailing List, Third Party Advisory
CPE cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

22 Feb 2022, 01:15

Type Values Removed Values Added
References
  • (GENTOO) https://security.gentoo.org/glsa/202202-03 -

04 Jan 2022, 12:15

Type Values Removed Values Added
References
  • (MLIST) https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html -

03 Jan 2022, 11:15

Type Values Removed Values Added
References
  • (DEBIAN) https://www.debian.org/security/2022/dsa-5034 -

29 Dec 2021, 16:15

Type Values Removed Values Added
References
  • (MLIST) https://lists.debian.org/debian-lts-announce/2021/12/msg00030.html -

21 Dec 2021, 20:45

Type Values Removed Values Added
CPE cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
References (DEBIAN) https://www.debian.org/security/2021/dsa-5026 - (DEBIAN) https://www.debian.org/security/2021/dsa-5026 - Third Party Advisory

20 Dec 2021, 00:15

Type Values Removed Values Added
References
  • (DEBIAN) https://www.debian.org/security/2021/dsa-5026 -

10 Dec 2021, 17:00

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown
v2 : 4.3
v3 : 6.5
CPE cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
CWE CWE-346
References (MISC) https://www.mozilla.org/security/advisories/mfsa2021-50/ - (MISC) https://www.mozilla.org/security/advisories/mfsa2021-50/ - Vendor Advisory
References (MISC) https://www.mozilla.org/security/advisories/mfsa2021-49/ - (MISC) https://www.mozilla.org/security/advisories/mfsa2021-49/ - Vendor Advisory
References (MISC) https://www.mozilla.org/security/advisories/mfsa2021-48/ - (MISC) https://www.mozilla.org/security/advisories/mfsa2021-48/ - Vendor Advisory
References (MISC) https://bugzilla.mozilla.org/show_bug.cgi?id=1730935 - (MISC) https://bugzilla.mozilla.org/show_bug.cgi?id=1730935 - Issue Tracking, Permissions Required, Vendor Advisory

08 Dec 2021, 22:15

Type Values Removed Values Added
New CVE

Information

Published : 2021-12-08 22:15

Updated : 2023-12-10 14:09


NVD link : CVE-2021-38507

Mitre link : CVE-2021-38507

CVE.ORG link : CVE-2021-38507


JSON object : View

Products Affected

mozilla

  • firefox
  • firefox_esr
  • thunderbird

debian

  • debian_linux
CWE
CWE-346

Origin Validation Error