An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. Due to a memory-management bug, it is vulnerable to a Denial of Service attack (against all clients using the proxy) via HTTP Range request processing.
総合評価: CVE-2021-31806 は高リスク（66/100）。CVSS 深刻度は中。悪用される可能性が高い（EPSS 95.78%、100 パーセンタイル） 根拠: EPSS 上、短期間での悪用可能性は高い水準です。 直近 1 日で EPSS が +10.61% 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: 悪用可能性が高いため、影響範囲の確認と修補の優先付けを推奨します。
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 | 85.18% | 95.78% | +10.61% |
| 2 | 2026-04-17 | 85.99% | 85.18% | -0.81% |
| 3 | 2026-03-04 | — | 85.99% | — |
EPSS の全履歴 （全 69 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 |
|---|---|---|---|---|---|---|
| 6.5 | 3.1 | MEDIUM |
|
2.8 | 3.6 | [email protected] |
| 4.0 | 2.0 | MEDIUM |
|
8.0 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
medium | CVE-2021-31806: 1 source package rows (squid); 45 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 35. | https://security.alpinelinux.org/vuln/CVE-2021-31806 |
debian
|
not yet assigned | CVE-2021-31806 not yet assigned priority: Debian including 1 source packages (squid), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2021-31806 |
gentoo
|
normal | CVE-2021-31806: 1 GLSA(s) (202105-14), 1 atom(s) (net-proxy/squid); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-31806 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2021-31806 |
suse
|
medium | — | https://www.suse.com/security/cve/CVE-2021-31806/ |
ubuntu
|
medium | CVE-2021-31806 medium priority: Ubuntu including 2 source packages (squid, squid3), 32 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 16, released 14, needed 1, needs-triage 1. | https://ubuntu.com/security/CVE-2021-31806 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| squid-cache | squid | < 4.15 | cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:* |
| squid-cache | squid | >= 5.0, < 5.0.6 | cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:* |
| debian | debian_linux | 9.0 | cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* |
| debian | debian_linux | 10.0 | cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* |
| fedoraproject | fedora | 33 | cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* |
| fedoraproject | fedora | 34 | cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* |
| netapp | cloud_manager | — | cpe:2.3:a:netapp:cloud_manager:-:*:*:*:*:*:*:* |
| URL | タグ |
|---|---|
| http://seclists.org/fulldisclosure/2023/Oct/14 | Mailing List Third Party Advisory |
| http://www.openwall.com/lists/oss-security/2023/10/11/3 | Mailing List Third Party Advisory |
| http://www.squid-cache.org/Versions/v4/changesets/squid-4-e7cf864f938f24eea8af0692c04d16790983c823.patch | Patch Vendor Advisory |
| https://github.com/squid-cache/squid/security/advisories/GHSA-pxwq-f3qr-w2xf | Patch Third Party Advisory |
| https://lists.debian.org/debian-lts-announce/2021/06/msg00014.html | Mailing List Third Party Advisory |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LSQ3U54ZCNXR44QRPW3AV2VCS6K3TKCF/ | |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T4EPIWUZDJAXADDHVOPKRBTQHPBR6H66/ | |
| https://security.netapp.com/advisory/ntap-20210716-0007/ | Third Party Advisory |
| https://www.debian.org/security/2021/dsa-4924 | Third Party Advisory |