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[email protected]CVE-2021-38507

HistoryDec 08, 2021 - 10:15 p.m.

CVE-2021-38507

2021-12-0822:15:08

CWE-346

[email protected]

web.nvd.nist.gov

177

cve-2021-38507

http2

rfc 8164

tls

same-origin

network attacker

firefox

thunderbird

nvd

4.3 Medium

CVSS2

Attack Vector

NETWORK

Attack Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

PARTIAL

Availability Impact

NONE

AV:N/AC:M/Au:N/C:N/I:P/A:N

6.5 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

7 High

AI Score

Confidence

High

0.002 Low

EPSS

Percentile

59.8%

JSON

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.

Affected configurations

Vulners

NVD

Node

mozillafirefoxRange≤94

mozillathunderbirdRange≤91.3

mozillafirefox_esrRange≤91.3

VendorProductVersionCPE
mozillafirefox*cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
mozillathunderbird*cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
mozillafirefox_esr*cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*

Vendor	Product	Version	CPE
mozilla	firefox	*	cpe:2.3:a:mozilla:firefox::::::::
mozilla	thunderbird	*	cpe:2.3:a:mozilla:thunderbird::::::::
mozilla	firefox_esr	*	cpe:2.3:a:mozilla:firefox_esr::::::::

CNA Affected

[
  {
    "product": "Firefox",
    "vendor": "Mozilla",
    "versions": [
      {
        "lessThan": "94",
        "status": "affected",
        "version": "unspecified",
        "versionType": "custom"
      }
    ]
  },
  {
    "product": "Thunderbird",
    "vendor": "Mozilla",
    "versions": [
      {
        "lessThan": "91.3",
        "status": "affected",
        "version": "unspecified",
        "versionType": "custom"
      }
    ]
  },
  {
    "product": "Firefox ESR",
    "vendor": "Mozilla",
    "versions": [
      {
        "lessThan": "91.3",
        "status": "affected",
        "version": "unspecified",
        "versionType": "custom"
      }
    ]
  }
]