h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. The QUIC stack (quicly), as used by H2O up to commit 43f86e5 (in version 2.3.0-beta and prior), is susceptible to a state exhaustion attack. When H2O is serving HTTP/3, a remote attacker can exploit this vulnerability to progressively increase the memory retained by the QUIC stack. This can eventually cause H2O to abort due to memory exhaustion. The vulnerability has been resolved in commit d67e81d03be12a9d53dc8271af6530f40164cd35. HTTP/1 and HTTP/2 are not affected by this vulnerability as they do not use QUIC. Administrators looking to mitigate this issue without upgrading can disable HTTP/3 support.
総合評価: CVE-2023-50247 は低リスク（33.8/100）。CVSS 深刻度は低。悪用される可能性が高い（EPSS 0.86%、53 パーセンタイル） 推奨対応: 悪用情報と EPSS の推移を監視し、必要に応じて優先度を見直してください。
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 | 0.62% | 0.86% | +0.24% |
| 2 | 2025-03-30 | 1.21% | 0.62% | -0.59% |
| 3 | 2025-03-29 | — | 1.21% | — |
EPSS の全履歴 （全 6 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] |
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
— | CVE-2023-50247: 1 source package rows (h2o); 3 state rows across 2 repos (3.19-community, edge-community); fixed 0, open 3. | https://security.alpinelinux.org/vuln/CVE-2023-50247 |
debian
|
unimportant | CVE-2023-50247 unimportant priority: Debian including 1 source packages (h2o), 2 status rows across 2 suites (bookworm, bullseye): resolved 2. | https://security-tracker.debian.org/tracker/CVE-2023-50247 |
| URL | タグ |
|---|---|
| https://github.com/h2o/h2o/commit/d67e81d03be12a9d53dc8271af6530f40164cd35 | Patch |
| https://github.com/h2o/h2o/security/advisories/GHSA-2ch5-p59c-7mv6 | Patch Vendor Advisory |