CVE-2026-42772 OpenSSL QUIC 流重组算法复杂度拒绝服务漏洞
影响远程攻击者可造成 CPU 资源耗尽，导致拒绝服务
OpenSSL 的 QUIC 实现在处理接收到的流分片时使用双向链表管理，对非顺序到达的分片会退化为从头到尾的线性查找。攻击者通过构造乱序的 STREAM 帧，可使重组算法复杂度达到 O(n²)，造成连接级 CPU 压力。该漏洞为算法复杂度问题（CWE-407），CVSS 评级为中危。
影响范围
受影响的是包含 QUIC 实现的 OpenSSL 版本；具体受影响版本范围暂无公开信息，建议以官方公告为准。FIPS 模块不受影响，因 QUIC 实现位于 FIPS 模块边界之外。
漏洞详情
漏洞类型为低效算法复杂度（CWE-407）。OpenSSL 用双向链表保存收到的 QUIC 流分片，仅对追加到链表尾部的操作做了优化，若分片不能紧接当前尾部，则回退为从链表头到尾部逐一线性查找。攻击者通过操纵分片偏移顺序，可迫使服务器执行 O(n²) 次操作，从而消耗大量 CPU 时间。
利用条件与风险
利用前提是攻击者能完成 QUIC 握手，并在通告的接收窗口内发送合规的 STREAM 帧，所需带宽较低。实战中可对单个连接造成 CPU 压力，进而可能引发拒绝服务。
修复建议
官方修复方案暂无公开信息，建议关注 OpenSSL 官方安全公告并及时升级到修复版本；临时缓解措施可考虑限制 QUIC 连接数或对异常乱序流量进行监控与限流。
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.