CVE-2023-6937 Improper (D)TLS key boundary enforcement

2024-02-1517:21:44

CWE-20

wolfSSL

www.cve.org

cve-2023-6937

(d)tls key

boundary enforcement

security vulnerability

5.3 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

LOW

Integrity Impact

NONE

Availability Impact

NONE

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

0.0004 Low

EPSS

Percentile

9.0%

JSON

wolfSSL prior to 5.6.6 did not check that messages in one (D)TLS record do not span key boundaries. As a result, it was possible to combine (D)TLS messages using different keys into one (D)TLS record. The most extreme edge case is that, in (D)TLS 1.3, it was possible that an unencrypted (D)TLS 1.3 record from the server containing first a ServerHello message and then the rest of the first server flight would be accepted by a wolfSSL client. In (D)TLS 1.3 the handshake is encrypted after the ServerHello but a wolfSSL client would accept an unencrypted flight from the server. This does not compromise key negotiation and authentication so it is assigned a low severity rating.

CNA Affected

[
  {
    "defaultStatus": "unaffected",
    "modules": [
      "(D)TLS"
    ],
    "product": "wolfSSL",
    "repo": "https://github.com/wolfSSL/wolfssl",
    "vendor": "wolfSSL",
    "versions": [
      {
        "lessThanOrEqual": "5.6.4",
        "status": "affected",
        "version": "0",
        "versionType": "release bundle"
      }
    ]
  }
]