A use-after-free vulnerability can occur while parsing an HTML5 stream in concert with custom HTML elements. This results in the stream parser object being freed while still in use, leading to a potentially exploitable crash. This vulnerability affects Thunderbird < 60.5, Firefox ESR < 60.5, and Firefox < 65.
総合評価: CVE-2018-18500 は高リスク（67.7/100）。CVSS 深刻度は重大。悪用される可能性が高い（EPSS 12.66%、96 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。 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 | 35.41% | 12.66% | -22.75% |
| 2 | 2026-05-29 | 33.41% | 35.41% | +2.00% |
| 3 | 2026-05-26 | — | 33.41% | — |
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 |
|---|---|---|---|---|---|---|
| 9.8 | 3.0 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
critical | CVE-2018-18500: 1 source package rows (firefox-esr); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0. | https://security.alpinelinux.org/vuln/CVE-2018-18500 |
debian
|
not yet assigned | CVE-2018-18500 not yet assigned priority: Debian including 3 source packages (firefox, firefox-esr, thunderbird), 11 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 11. | https://security-tracker.debian.org/tracker/CVE-2018-18500 |
gentoo
|
normal | CVE-2018-18500: 2 GLSA(s) (201903-04, 201904-07), 4 atom(s) (mail-client/thunderbird, mail-client/thunderbird-bin, www-client/firefox, www-client/firefox-bin); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2018-18500 |
redhat
|
critical | — | https://access.redhat.com/security/cve/CVE-2018-18500 |
suse
|
medium | CVE-2018-18500 severity moderate: SUSE including 184 source package names (1.0.0.1862.1.5.2:libfreebl3-3.41.1-3.13.1, 1.0.0.1862.1.5.2:libsoftokn3-3.41.1-3.13.1, …), 743 product×package rows across 122 product lines (Container bci/openjdk, Container bci/openjdk-devel, … (122 product lines)): Fixed 694, Known Not Affected 49. | https://www.suse.com/security/cve/CVE-2018-18500/ |
ubuntu
|
medium | CVE-2018-18500 medium priority: Ubuntu including 5 source packages (firefox, mozjs38, mozjs52, mozjs60, thunderbird), 80 status rows across 16 suites (bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): DNE 35, released 32, ignored 13. | https://ubuntu.com/security/CVE-2018-18500 |
| ベンダー | 製品 | バージョン | 生の CPE |
|---|---|---|---|
| mozilla | firefox | < 65.0 | cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* |
| mozilla | firefox_esr | < 60.5 | cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* |
| mozilla | thunderbird | < 60.5 | cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* |
| canonical | ubuntu_linux | 14.04 | cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:* |
| canonical | ubuntu_linux | 16.04 | cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:* |
| canonical | ubuntu_linux | 18.04 | cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:* |
| canonical | ubuntu_linux | 18.10 | cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:* |
| debian | debian_linux | 8.0 | cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:* |
| debian | debian_linux | 9.0 | cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_desktop | 6.0 | cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_desktop | 7.0 | cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_server | 6.0 | cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_server | 7.0 | cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_server_aus | 7.6 | cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:* |
| redhat | enterprise_linux_server_eus | 7.6 | cpe:2.3:o:redhat:enterprise_linux_server_eus:7.6:*:*:*:*:*:*:* |
| redhat | enterprise_linux_server_tus | 7.6 | cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:* |
| redhat | enterprise_linux_workstation | 6.0 | cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:* |
| redhat | enterprise_linux_workstation | 7.0 | cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:* |