Origin Validation Error Affecting firefox-esr package, versions <91.3.0esr-1


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.71% (82nd percentile)

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  • Snyk IDSNYK-DEBIAN12-FIREFOXESR-1909778
  • published3 Nov 2021
  • disclosed8 Dec 2021

Introduced: 3 Nov 2021

CVE-2021-38507  (opens in a new tab)
CWE-346  (opens in a new tab)

How to fix?

Upgrade Debian:12 firefox-esr to version 91.3.0esr-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream firefox-esr package and not the firefox-esr package as distributed by Debian. See How to fix? for Debian:12 relevant fixed versions and status.

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.

CVSS Scores

version 3.1