CVE detail
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.
Buzz score
Why this CVE is surfacing
This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.
Buzz score components · mention 11.0 · diversity 6.5 · KEV 0.0 · OTX 0.0 · PoC 0.0
Why it matters now
Mention timeline
- Total mentions
- 0
- within the 30d window
- Peak daily
- 0
- highest bucket
Evidence
Source links by recency
2 source links · newest first
Mozilla this week announced that Firefox 94 is bringing Site Isolation to all users, along with patches for over a dozen vulnerabilities, including seven that feature a high severity rating.
newswww.securityweek.comNov 4, 2021, 3:41 PM- Update now! Mozilla fixes security vulnerabilities in Firefox 94Malwarebytes Labs
In a security advisory, Mozilla’s announced that several security issues in its Firefox browser have been fixed. Several of these vulnerabilities…
newswww.malwarebytes.comNov 2, 2021, 5:00 PM
Exploit code
Public exploit repository references
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0 repository references · best confidence N/A · max 0 stars
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