CVE-2026-42772— Potential CPU DoS via O(n^2) Fragment Reassembly in QUIC
Quick assessment
Affected
OpenSSL OpenSSL
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
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 da
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I. Basic Information for CVE-2026-42772
Vulnerability Information
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Vulnerability Title
Potential CPU DoS via O(n^2) Fragment Reassembly in QUIC
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
算法复杂性
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-42772
| # | POC Description | Source Link | Shenlong Link |
|---|
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Other References for CVE-2026-42772 (5)
-
https://openssl-library.org/news/secadv/20260929.txt vendor-advisory
Same Patch Batch · OpenSSL · 2026-09-29 · 14 CVEs total
| CVE-2026-35189 | Excessive Memory Allocation in Relative CRLDP Processing | |
| CVE-2026-35191 | QUIC Unvalidated Amplification Credit may be Over Accounted | |
| CVE-2026-75806 | Unauthenticated and Undersized DTLS 1.2 AEAD Record Causes DoS | |
| CVE-2026-75804 | QUIC Connection-Level Flow Control is Not Enforced for Streams | |
| CVE-2026-75805 | NULL Pointer Dereference in CMP Client Revocation Response Handling | |
| CVE-2026-54873 | QUIC STREAM Fragment Metadata DoS | |
| CVE-2026-54872 | Timing Side-Channel in Scalar Multiplication for Non-NIST EC Curves | |
| CVE-2026-54875 | Non-Constant-Time SM2 Scalar Multiplication on ARM64 and RISC-V | |
| CVE-2026-77696 | Timing Side-Channel in SM2 Signature Generation | |
| CVE-2026-72897 | Out-of-Bounds Access After SSL_set_SSL_CTX() During a Handshake | |
| CVE-2026-84782 | DTLS Retransmits Handshake Messages From a Stale Buffer Offset | |
| CVE-2026-84784 | QUIC: Unbounded RETIRE_CONNECTION_ID Backlog | |
| CVE-2026-84783 | Use-After-Free in X.509 Extension Cache Under Concurrent Use |
IV. Related Vulnerabilities
Same product: OpenSSL
-
CVE-2026-84784
QUIC: Unbounded RETIRE_CONNECTION_ID Backlog -
CVE-2026-84783
Use-After-Free in X.509 Extension Cache Under Concurrent Use -
CVE-2026-84782
DTLS Retransmits Handshake Messages From a Stale Buffer Offs -
CVE-2026-77696
Timing Side-Channel in SM2 Signature Generation -
CVE-2026-75806
Unauthenticated and Undersized DTLS 1.2 AEAD Record Causes D
Same vendor: OpenSSL
-
CVE-2026-84784
QUIC: Unbounded RETIRE_CONNECTION_ID Backlog -
CVE-2026-84783
Use-After-Free in X.509 Extension Cache Under Concurrent Use -
CVE-2026-84782
DTLS Retransmits Handshake Messages From a Stale Buffer Offs -
CVE-2026-77696
Timing Side-Channel in SM2 Signature Generation -
CVE-2026-75806
Unauthenticated and Undersized DTLS 1.2 AEAD Record Causes D
Same weakness: CWE-407
-
CVE-2026-100700
nodemailer before 10.0.6 Denial of Service via addressparser -
CVE-2026-67419
RabbitMQ: Consecutive topic wildcards cause combinatorial ro -
CVE-2026-65634
Superlinear CPU denial of service in Erlang/OTP ASN.1 OBJECT -
CVE-2026-87081
Net::IDN::UTS46 versions before 2.590 for Perl allow CPU exh -
CVE-2026-87079
Net::IDN::Punycode versions before 2.590 for Perl allow CPU
V. Comments for CVE-2026-42772
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