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.
総合評価: CVE-2021-3618 は中リスク（58.5/100）。CVSS 深刻度は高。悪用される可能性が高い（EPSS 2.04%、79 パーセンタイル） 根拠: 直近 1 日で EPSS が +1.42% 上昇。悪用への関心が高まっている可能性があります。 推奨対応: 影響資産を整理し、修補計画に組み込んでください。
リスクは変動します。再評価に基づき、本ページの表示内容を更新しています。
EPSS は日次で悪用されやすさの相対度合いを推定します。パーセンタイルは採点済み CVE の中での相対位置（高いほど相対的に深刻）を示します。
| # | 日付 | 旧 EPSS スコア | 新 EPSS スコア | Δ（新 − 旧） |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.61% | 2.04% | +1.42% |
| 2 | 2026-03-04 | 0.32% | 0.61% | +0.29% |
| 3 | 2026-03-01 | — | 0.32% | — |
EPSS の全履歴 （全 43 件）
この CVE の CVSS 指標。
| ベーススコア | バージョン | 深刻度 | ベクトル | 悪用しやすさ | 影響 | スコアの出典 |
|---|---|---|---|---|---|---|
| 7.4 | 3.1 | HIGH |
|
2.2 | 5.2 | [email protected] |
| 5.8 | 2.0 | MEDIUM |
|
8.6 | 4.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
high | CVE-2021-3618: 1 source package rows (nginx); 39 state rows across 8 repos (3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 13, open 26. | https://security.alpinelinux.org/vuln/CVE-2021-3618 |
debian
|
not yet assigned | CVE-2021-3618 not yet assigned priority: Debian including 3 source packages (nginx, sendmail, vsftpd), 15 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 12, open 3. | https://security-tracker.debian.org/tracker/CVE-2021-3618 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2021-3618 |
suse
|
high | CVE-2021-3618 severity important: SUSE including 24 source package names (go1.17, go1.17-doc, …), 154 product×package rows across 57 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (57 product lines)): Fixed 73, Will Not Fix 42, Known Not Affected 39. | https://www.suse.com/security/cve/CVE-2021-3618/ |
ubuntu
|
low | CVE-2021-3618 low priority: Ubuntu including 3 source packages (nginx, sendmail, vsftpd), 45 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 20, released 9, needed 8, ignored 7, needs-triage 1. | https://ubuntu.com/security/CVE-2021-3618 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| f5 | nginx | < 1.21.0 | cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:* |
| sendmail | sendmail | < 8.17 | cpe:2.3:a:sendmail:sendmail:*:*:*:*:*:*:*:* |
| vsftpd_project | vsftpd | < 3.0.4 | cpe:2.3:a:vsftpd_project:vsftpd:*:*:*:*:*:*:*:* |
| fedoraproject | fedora | 33 | cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* |
| fedoraproject | fedora | 34 | cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* |
| fedoraproject | fedora | 35 | cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* |
| debian | debian_linux | 10.0 | cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* |
| URL | タグ |
|---|---|
| https://alpaca-attack.com/ | Third Party Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=1975623 | Issue Tracking Patch Third Party Advisory |
| https://lists.debian.org/debian-lts-announce/2022/11/msg00031.html | Mailing List Third Party Advisory |