CVE-2021-38507
CVSS V2 Medium 4.3
CVSS V3 Medium 6.5
Description
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.
Overview
- CVE ID
- CVE-2021-38507
- Assigner
- security@mozilla.org
- Vulnerability Status
- Analyzed
- Published Version
- 2021-12-08T22:15:08
- Last Modified Date
- 2022-12-09T15:54:38
Weakness Enumerations
CPE Configuration (Product)
| CPE | Vulnerable | Operator | Version Start | Version End |
|---|---|---|---|---|
| cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* | 1 | OR | 94.0 | |
| cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* | 1 | OR | 91.3.0 | |
| cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* | 1 | OR | 91.3.0 | |
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | 1 | OR | ||
| cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* | 1 | OR | ||
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* | 1 | OR |
CVSS Version 2
- Version
- 2.0
- Vector String
- AV:N/AC:M/Au:N/C:N/I:P/A:N
- Access Vector
- NETWORK
- Access Compatibility
- MEDIUM
- Authentication
- NONE
- Confidentiality Impact
- NONE
- Integrity Impact
- PARTIAL
- Availability Impact
- NONE
- Base Score
- 4.3
- Severity
- MEDIUM
- Exploitability Score
- 8.6
- Impact Score
- 2.9
CVSS Version 3
- Version
- 3.1
- Vector String
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- Attack Vector
- NETWORK
- Attack Compatibility
- LOW
- Privileges Required
- NONE
- User Interaction
- REQUIRED
- Scope
- UNCHANGED
- Confidentiality Impact
- NONE
- Availability Impact
- NONE
- Base Score
- 6.5
- Base Severity
- MEDIUM
- Exploitability Score
- 2.8
- Impact Score
- 3.6
References
| Reference URL | Reference Tags |
|---|---|
| https://bugzilla.mozilla.org/show_bug.cgi?id=1730935 | Issue Tracking Permissions Required Vendor Advisory |
| https://lists.debian.org/debian-lts-announce/2021/12/msg00030.html | Mailing List Third Party Advisory |
| https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html | Mailing List Third Party Advisory |
| https://security.gentoo.org/glsa/202202-03 | Third Party Advisory |
| https://security.gentoo.org/glsa/202208-14 | |
| https://www.debian.org/security/2021/dsa-5026 | Third Party Advisory |
| https://www.debian.org/security/2022/dsa-5034 | Third Party Advisory |
| https://www.mozilla.org/security/advisories/mfsa2021-48/ | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2021-49/ | Vendor Advisory |
| https://www.mozilla.org/security/advisories/mfsa2021-50/ | Vendor Advisory |
Sources
| Source Name | Source URL |
|---|---|
| NIST | https://nvd.nist.gov/vuln/detail/CVE-2021-38507 |
| MITRE | https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-38507 |
History
| Created | Old Value | New Value | Data Type | Notes |
|---|---|---|---|---|
| 2022-05-10 15:45:41 | Added to TrackCVE | |||
| 2022-12-06 03:24:49 | 2021-12-08T22:15Z | 2021-12-08T22:15:08 | CVE Published Date | updated |
| 2022-12-06 03:24:49 | 2022-08-10T20:15:21 | CVE Modified Date | updated | |
| 2022-12-06 03:24:49 | Undergoing Analysis | Vulnerability Status | updated | |
| 2022-12-06 03:24:54 | References | updated | ||
| 2022-12-09 16:13:14 | 2022-12-09T15:54:38 | CVE Modified Date | updated | |
| 2022-12-09 16:13:14 | Undergoing Analysis | Analyzed | Vulnerability Status | updated |