A flaw was found in dnsmasq before version 2.83. When receiving a query, dnsmasq does not check for an existing pending request for the same name and forwards a new request. By default, a maximum of 150 pending queries can be sent to upstream servers, so there can be at most 150 queries for the same name. This flaw allows an off-path attacker on the network to substantially reduce the number of attempts that it would have to perform to forge a reply and have it accepted by dnsmasq. This issue is mentioned in the "Birthday Attacks" section of RFC5452. If chained with CVE-2020-25684, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
総合評価: CVE-2020-25686 は中リスク（51/100）。CVSS 深刻度は低。悪用される可能性が高い（EPSS 4.91%、91 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 +4.36% 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 | 0.55% | 4.91% | +4.36% |
| 2 | 2026-05-28 | 0.41% | 0.55% | +0.14% |
| 3 | 2026-03-26 | — | 0.41% | — |
EPSS の全履歴 （全 31 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 |
|---|---|---|---|---|---|---|
| 3.7 | 3.1 | LOW |
|
2.2 | 1.4 | [email protected] |
| 4.3 | 2.0 | MEDIUM |
|
8.6 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
— | CVE-2020-25686: 1 source package rows (dnsmasq); 25 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 15. | https://security.alpinelinux.org/vuln/CVE-2020-25686 |
debian
|
not yet assigned | CVE-2020-25686 not yet assigned priority: Debian including 1 source packages (dnsmasq), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2020-25686 |
gentoo
|
normal | CVE-2020-25686: 1 GLSA(s) (202101-17), 1 atom(s) (net-dns/dnsmasq); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-25686 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2020-25686 |
suse
|
high | CVE-2020-25686 severity important: SUSE including 27 source package names (0.38.1.5.8.40:dnsmasq-2.78-7.6.1, 0.45.0.8.14.1:dnsmasq-2.78-7.6.1, …), 66 product×package rows across 54 product lines (Container suse/sles/15.2/virt-launcher, Container suse/sles/15.3/virt-launcher, … (54 product lines)): Fixed 66. | https://www.suse.com/security/cve/CVE-2020-25686/ |
ubuntu
|
medium | CVE-2020-25686 medium priority: Ubuntu including 1 source packages (dnsmasq), 15 status rows across 15 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): released 14, ignored 1. | https://ubuntu.com/security/CVE-2020-25686 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| thekelleys | dnsmasq | < 2.83 | cpe:2.3:a:thekelleys:dnsmasq:*:*:*:*:*:*:*:* |
| fedoraproject | fedora | 32 | cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:* |
| fedoraproject | fedora | 33 | cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* |
| debian | debian_linux | 10.0 | cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* |
| arista | eos | >= 4.21, < 4.21.14m | cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* |
| arista | eos | >= 4.22, < 4.22.9m | cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* |
| arista | eos | >= 4.23, < 4.23.7m | cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* |
| arista | eos | >= 4.24, < 4.24.5m | cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* |
| arista | eos | >= 4.25, < 4.25.2f | cpe:2.3:o:arista:eos:*:*:*:*:*:*:*:* |