OpenSSLに脆弱性（CVE-2026-42772）
概要
OpenSSLに脆弱性が確認されました。
バージョン 3.4.0 以上 3.4.8 未満、3.5.0 以上 3.5.9 未満、3.6.0 以上 3.6.5 未満、4.0.0 以上 4.0.3 未満に影響があります。
修正版 3.4.8 / 3.5.9 / 3.6.5 / 4.0.3 への更新が推奨されます。
脆弱性の基本情報
| 脆弱性ID | CVE-2026-42772 |
|---|---|
| 脆弱性の種類 | CWE-407 |
| 危険度 | 中 |
| CVSSスコア |
5.3（CVSS v3.1） CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| 公開日 | 2026年9月29日 |
| 更新日 | 2026年10月8日 |
影響を受ける製品
| 製品 | 影響を受けるバージョン | 修正版 | 出典 |
|---|---|---|---|
| OpenSSL |
3.4.0 以上 3.4.8 未満、3.5.0 以上 3.5.9 未満、3.6.0 以上 3.6.5 未満、4.0.0 以上 4.0.3 未満 | 3.4.8 / 3.5.9 / 3.6.5 / 4.0.3 | NVD（National Vulnerability Database / NIST） |
推奨対応
- OpenSSLを、ご利用中の系列に対応する修正版（3.4.8 / 3.5.9 / 3.6.5 / 4.0.3）またはそれ以降の公式最新版へ更新してください。
- OpenSSLを OS・ディストリビューションのパッケージで利用している場合は、提供元の公式セキュリティ更新が適用されているかを確認してください（独自に修正が取り込まれている場合があります）。
情報元の原文
NVD（National Vulnerability Database / NIST）
Issue summary: The QUIC stream reassembly algorithm performance deteriorates
progressively as packets are arriving out of order. The worst case has
a quadratic complexity proportional to the number of stream frames kept in
the buffer for the received stream data.
Impact summary: A remote QUIC peer that completes the handshake can create
a connection-scoped CPU pressure and potentially a Denial of Service using
compliant STREAM frames inside the advertised receive window, with low
attacker bandwidth.
CWE: CWE-407: Inefficient Algorithmic Complexity
Description: OpenSSL manages received QUIC stream fragments using a
doubly-linked list. While it optimizes for append operations (at the end of
the list), it falls back to a head-to-tail linear search for any fragment
that does not immediately follow the current `tail`.
By manipulating the sequence of offsets, an attacker can force the server
to perform O(n^2) operations, consuming excessive CPU time for the
QUIC process.
FIPS impact: no
The FIPS module is not affected as the QUIC implementation is outside of
the OpenSSL FIPS module boundary.
利用条件：米国政府の著作物（パブリックドメイン）・原文のまま掲載
Copyright 1999-2026 The MITRE Corporation
CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
CVE List（CVE Program）
Potential CPU DoS via O(n^2) Fragment Reassembly in QUIC
Issue summary: The QUIC stream reassembly algorithm performance deteriorates
progressively as packets are arriving out of order. The worst case has
a quadratic complexity proportional to the number of stream frames kept in
the buffer for the received stream data.
Impact summary: A remote QUIC peer that completes the handshake can create
a connection-scoped CPU pressure and potentially a Denial of Service using
compliant STREAM frames inside the advertised receive window, with low
attacker bandwidth.
CWE: CWE-407: Inefficient Algorithmic Complexity
Description: OpenSSL manages received QUIC stream fragments using a
doubly-linked list. While it optimizes for append operations (at the end of
the list), it falls back to a head-to-tail linear search for any fragment
that does not immediately follow the current `tail`.
By manipulating the sequence of offsets, an attacker can force the server
to perform O(n^2) operations, consuming excessive CPU time for the
QUIC process.
FIPS impact: no
The FIPS module is not affected as the QUIC implementation is outside of
the OpenSSL FIPS module boundary.
利用条件：CVE の利用条件（CVE Terms of Use）・原文のまま掲載
Copyright 1999-2026 The MITRE Corporation
CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.
情報元
- NVD（National Vulnerability Database / NIST）
https://nvd.nist.gov/vuln/detail/CVE-2026-42772 - CVE List（CVE Program）
https://www.cve.org/CVERecord?id=CVE-2026-42772