CVEvulnerability

CVE-2021-3618

7.4 HIGH Published 2022-03-23 Modified 2026-06-17 Official page ↗
Status
Modified
Published
2022-03-23
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
7.4 HIGH — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS 2.0 ([email protected])
5.8 MEDIUM — AV:N/AC:M/Au:N/C:P/I:P/A:N
Weaknesses
CWE-295

Description

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

Affected configurations

• f5 nginx (< 1.21.0) • sendmail sendmail (< 8.17) • vsftpd project vsftpd (< 3.0.4) • fedoraproject fedora 33 • fedoraproject fedora 34 • fedoraproject fedora 35 • debian debian linux 10.0

Related

Weakness · CWE (1)

  • CWE-295 Improper Certificate Validation weakness

References