CVE-2021-3618
HIGHEPSS 79th pctlDescription
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.
How to fix
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Exploit Intelligence
Elevated risk: more likely to be exploited than 79% of all known CVEs.
References
Related Vulnerabilities
Other CWE-295 (Improper Certificate Validation) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2015-4000 | Low | 3.7 | 100% | - | Fix |
| CVE-2020-0601 | High | 8.1 | 89% | KEV | Fix |
| CVE-2009-3555 | Critical | 9.8 | 87% | - | Fix |
| CVE-2022-26923 | High | 8.8 | 83% | KEV | Fix |
| CVE-2023-27823 | Critical | 9.8 | 53% | - | - |
| CVE-2022-42979 | High | 8.8 | 24% | - | - |
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Markdown
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.