CVE-2021-3618
HIGH7.4EPSS 0.61%nginx - security update
Published: 3/23/2022Modified: 4/28/2026
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 packages (7)
- Alpine/nginxfrom 0, < 1.20.1-r1
- Bitnami/nginxfrom 0, < 1.21.0
- Bitnami/nginx-gatewayfrom 0, < 1.21.0
- Debian/nginxfrom 0, < 1.14.2-2+deb10u5
- Debian/nginxfrom 0, < 1.18.0-6.1+deb11u2
- Debian/sendmailfrom 0
- Debian/vsftpdfrom 0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
References (6)
- ADVISORYhttps://security.alpinelinux.org/vuln/CVE-2021-3618
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-3618
- WEBhttps://alpaca-attack.com/
- WEBhttps://bugzilla.redhat.com/show_bug.cgi?id=1975623
- WEBhttps://lists.debian.org/debian-lts-announce/2022/11/msg00031.html
- WEBhttps://nvd.nist.gov/vuln/detail/CVE-2021-3618