All vulnerabilities

Servers and applications

CVE-2021-3618

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…

Severity
High 7.4
Published
23 Mar 2022
Last changed
17 Jun 2026
Added to UpHeron
21 Oct 2026
Fixed in
1.21.0
Sources
NVD

Affected software

SoftwareAffected versions
nginxServers and applications · cpe:a:f5:nginx
  • Every version before 1.21.0

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2021-3618
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2021-3618