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CVE-2026-44894— Netty's Default QUIC token handler accepts any client-supplied token

Quick assessment

Affected
netty netty
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Netty是Netty团队开源的一款非阻塞I/O客户端-服务器框架, 它主要用于开发Java网络应用程序,如协议服务器和客户端等。 Netty 4.2.15.Final之前版本存在授权问题漏洞，该漏洞源于NoQuicTokenHandler的validateToken()无条件返回0，导致服务器将包含任意非空令牌字节的初始数据包视为已验证地址，从而绕过3倍反放大发送限制，攻击者可通过伪造受害者源IP，反射全尺寸握手响应。

CVSS 7.5 · High EPSS 0.19% · P8

Affected Version Matrix 1

VendorProduct Version RangeStatus
netty netty >= 4.2.0.Final, < 4.2.15.Final affected
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I. Basic Information for CVE-2026-44894

Vulnerability Information
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Vulnerability Title
Netty's Default QUIC token handler accepts any client-supplied token
Source: CVE Program / CVE List V5
Vulnerability Description
Netty is a network application framework for development of protocol servers and clients. NoQuicTokenHandler is the tokenHandler used when the application does not set one. Prior to version 4.2.15.Final, its writeToken() returns false (server will not send Retry — acceptable), but validateToken() unconditionally `return 0`. In QuicheQuicServerCodec.handlePacket(), a non-negative return from validateToken() is interpreted as 'token is valid, ODCID starts at offset 0', causing the server to call quiche_accept as if the client's address had been validated by a Retry round-trip. Per RFC 9000 §8.1, a validated address lifts the 3× anti-amplification send limit. Thus any attacker who includes ANY non-empty token bytes in an Initial packet — with a spoofed victim source IP — causes the Netty server to treat the victim as validated and reflect full-size handshake flights (certificates, etc.) toward it without the 3× cap. The correct 'no token handler' semantics would be to return -1 (invalid) so the normal un-validated path and amplification limit apply. Version 4.2.15.Final patches the issue.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
通信信道源的不正确验证
Source: CVE Program / CVE List V5
Vulnerability Title
Netty 授权问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Netty是Netty团队开源的一款非阻塞I/O客户端-服务器框架, 它主要用于开发Java网络应用程序,如协议服务器和客户端等。 Netty 4.2.15.Final之前版本存在授权问题漏洞，该漏洞源于NoQuicTokenHandler的validateToken()无条件返回0，导致服务器将包含任意非空令牌字节的初始数据包视为已验证地址，从而绕过3倍反放大发送限制，攻击者可通过伪造受害者源IP，反射全尺寸握手响应。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
netty netty >= 4.2.0.Final, < 4.2.15.Final -

II. Public POCs for CVE-2026-44894

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Qwen3.6-35B-A3B · 11580 chars
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III. Intelligence Information for CVE-2026-44894

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Vendor Advisories for CVE-2026-44894 (1)

Vendor Pages for CVE-2026-44894 (1)

Same Patch Batch · netty · 2026-06-12 · 19 CVEs total

CVE-2026-45674 8.7 HIGH Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records
CVE-2026-47691 8.7 HIGH Netty has Insufficient Bailiwick Validation for NS Records
CVE-2026-48059 8.7 HIGH Netty HAProxy: Unbalanced Reference Count in Nested PP2_TYPE_SSL TLV Parsing Leads to Memo
CVE-2026-48006 8.7 HIGH Netty's Lack of Lifecycle Cleanup Leads to Pooled ByteBuf Leak in RedisArrayAggregator
CVE-2026-44892 7.5 HIGH Netty has a Vulnerable Default Configuration Which Leads to Denial of Service via Unbounde
CVE-2026-44893 7.5 HIGH Netty: HAProxy SSL TLV parsing leaks retained slice on invalid TLV length
CVE-2026-46340 7.5 HIGH Netty: SCTP reassembly nests buffers without bound
CVE-2026-50011 7.5 HIGH Netty has unbounded pre-allocation in RedisArrayAggregator from RESP array length
CVE-2026-50010 7.5 HIGH Netty's wrapping plain trust manager silently disables hostname verification
CVE-2026-48748 7.5 HIGH Netty HTTP/3 QPACK Blocked Streams Memory Exhaustion
CVE-2026-45416 7.5 HIGH Netty: SNI handler pre-allocates up to 16 MiB from nine attacker bytes
CVE-2026-45673 6.8 MEDIUM Netty: DNS Cache Poisoning due to Predictable PRNG and Default Static Source Port
CVE-2026-48043 5.3 MEDIUM netty-codec-http2: ByteBuf Reference-Count Leak in DelegatingDecompressorFrameListener Lea
CVE-2026-47244 5.3 MEDIUM Netty HTTP/2: Advertised MAX_CONCURRENT_STREAMS are not enforced
CVE-2026-50020 5.3 MEDIUM Netty's HttpObjectDecoder skips arbitrary initial control characters when only initial CRL
CVE-2026-50009 4.8 MEDIUM Netty QUIC stateless reset token material exposed through header-visible connection IDs
CVE-2026-45536 4.0 MEDIUM Netty: Unix-socket fd receive leaks descriptors when peer sends two at once
CVE-2026-50560 Netty susceptible to HTTP/2 Reset Attack with different on-the-wire signature

IV. Related Vulnerabilities

Same product: netty
Same vendor: netty
Same weakness: CWE-940

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