CVE-2026-45674

Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, Netty's DnsResolveContext fails to validate the origin (bailiwick) of CNAME records in DNS responses. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVSS 3.1 · 8.7 High EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-45416

Netty: SNI handler pre-allocates up to 16 MiB from nine attacker bytes

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, SslClientHelloHandler.decode() reads the 24-bit TLS handshake length and, when the ClientHello does not fit in the first record, eagerly allocates `ctx.alloc().buffer(handshakeLength)` (line 161). The guard at line 140 is `handshakeLength > maxClientHelloLength && maxClientHelloLength != 0`, and the commonly-used SniHandler/AbstractSniHandler constructors (SniHandler(Mapping), SniHandler(AsyncMapping), AbstractSniHandler()) pass maxClientHelloLength=0 and handshakeTimeoutMillis=0, so the length guard is disabled and no timeout is scheduled. A 16 MiB request exceeds the default pooled chunk size and becomes a huge/unpooled allocation performed immediately. The buffer is retained in the handler until the channel closes. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-44893

Netty: HAProxy SSL TLV parsing leaks retained slice on invalid TLV length

Netty is a network application framework for development of protocol servers and clients. In netty-codec-haproxy prior to versions 4.1.135.Final and 4.2.15.Final, when decoding a PP2_TYPE_SSL TLV, HAProxyMessage.readNextTLV() first calls `header.retainedSlice(header.readerIndex(), length)` and only then reads the 1-byte client field and 4-byte verify field. If the attacker sets the TLV length below 5, the subsequent readByte/readInt throws IndexOutOfBoundsException. HAProxyMessageDecoder only catches HAProxyProtocolException around this call, so the IOOBE propagates and the retained slice on the pooled cumulation buffer is never released. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-44890

Netty has Unbounded Direct Memory Consumption in its RedisDecoder

Netty is a network application framework for development of protocol servers and clients. In netty-codec-redis prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can cause DoS by sending crafted Redis payloads across multiple connections without `\r\n`. This exhausts the server's direct memory pool (OutOfDirectMemoryError), preventing legitimate connections from being processed. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-44250

Netty: Memory Exhaustion in RedisArrayAggregator due to Deeply Nested Arrays

Netty is a network application framework for development of protocol servers and clients. In netty-codec-redis prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can cause DoS by sending a crafted Redis payload with deeply nested arrays. This forces the server to allocate a massive number of state objects and collections, leading to memory exhaustion and an OutOfMemoryError. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-44249

Netty has an IPv6 Subnet Filter Bypass via Incorrect Comparator Masking

Netty is a network application framework for development of protocol servers and clients. In netty-handler prior to versions 4.1.135.Final and 4.2.15.Final, an attacker can bypass IPv6 subnet rules due to an incorrect masking operation in IpSubnetFilterRule.compareTo(). Valid public IP addresses can bypass the restrictions. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-42587

Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy enables decompression bomb DoS

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Io.netty Netty

Products

Netty-codec-http Netty-codec-http2 Netty

CVE-2026-42584

Netty: HttpClientCodec response desynchronization

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpClientCodec pairs each inbound response with an outbound request by queue.poll() once per response, including for 1xx. If the client pipelines GET then HEAD and the server sends 103, then 200 with GET body, then 200 for HEAD, the queue pairs HEAD with the first 200. The HEAD rule then skips reading that message’s body, so the GET entity bytes stay on the stream and the following 200 is parsed from the wrong offset. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS 3.1 · 7.3 High EPSS < 1% KEV · Not listed

Vendors

Io.netty Netty

Products

Netty-codec-http Netty

CVE-2026-42581

Netty: HTTP/1.0 TE+CL Coexistence Bypasses Smuggling Sanitization

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpObjectDecoder strips a conflicting Content-Length header when a request carries both Transfer-Encoding: chunked and Content-Length, but only for HTTP/1.1 messages. The guard is absent for HTTP/1.0. An attacker that sends an HTTP/1.0 request with both headers causes Netty to decode the body as chunked while leaving Content-Length intact in the forwarded HttpMessage. Any downstream proxy or handler that trusts Content-Length over Transfer-Encoding will disagree on message boundaries, enabling request smuggling. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS 3.1 · 5.8 Medium EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-42579

Netty: DNS Codec Input Validation Bypass in Netty (Encoder + Decoder)

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's DNS codec does not enforce RFC 1035 domain name constraints during either encoding or decoding. This creates a bidirectional attack surface: malicious DNS responses can exploit the decoder, and user-influenced hostnames can exploit the encoder. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS 3.1 · 7.5 High EPSS 1.0% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-42578

Netty: HTTP Header Injection via HttpProxyHandler Disabled Validation

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders without any CRLF validation. This allows an attacker who can influence the outbound headers to inject arbitrary HTTP headers into the CONNECT request sent to the proxy server. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS 4.0 · 2.9 Low EPSS 1.1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-54251

netty-incubator-codec-ohttp: [OHttpServerCodec] Native Direct-Memory Leak on AEAD Decryption Failure Leads to Gateway Denial of Service

netty-incubator-codec-ohttp implements Oblivious HTTP (OHTTP) gateway and client functionality using Netty. Prior to 0.0.23.Final, the OHTTP gateway decryption path in codec-ohttp/src/main/java/io/netty/incubator/codec/ohttp/OHttpRequestResponseContext.java allocates a pooled direct ByteBuf for decrypted plaintext before the AEAD tag is verified. When an invalid tag causes decryptChunk() to throw CryptoException, OHttpRequestResponseContext.decodeChunk() does not release the ByteBuf because the allocation is not guarded by try/finally. Repeated invalid encrypted requests can therefore leak native off-heap memory until the gateway is unable to continue serving requests. This issue is fixed in version 0.0.23.Final.

CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty-incubator-codec-ohttp

CVE-2026-44248

Netty: Resource exhaustion in MqttDecoder

Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the MQTT 5 header Properties section is parsed and buffered before any message size limit is applied. Specifically, in MqttDecoder, the decodeVariableHeader() method is called before the bytesRemainingBeforeVariableHeader > maxBytesInMessage check. The decodeVariableHeader() can call other methods which will call decodeProperties(). Effectively, Netty does not apply any limits to the size of the properties being decoded. Additionally, because MqttDecoder extends ReplayingDecoder, Netty will repeatedly re-parse the enormous Properties sections and buffer the bytes in memory, until the entire thing parses to completion. This can cause high resource usage in both CPU and memory. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed

Vendors

Io.netty Netty

Products

Netty-codec-mqtt Netty

CVE-2026-33871

Netty HTTP/2 CONTINUATION Frame Flood DoS via Zero-Byte Frame Bypass

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, a remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of `CONTINUATION` frames. The server's lack of a limit on the number of `CONTINUATION` frames, combined with a bypass of existing size-based mitigations using zero-byte frames, allows an user to cause excessive CPU consumption with minimal bandwidth, rendering the server unresponsive. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

CVSS 4.0 · 8.7 High EPSS 1.4% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-33870

Netty: HTTP Request Smuggling via Chunked Extension Quoted-String Parsing

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-62380

Netty before 4.2.16.Final SOCKS Proxy Null Byte Injection

Netty (io.netty:netty-codec-socks) versions 4.2.0.Final through 4.2.16.Final and 4.1.x through 4.1.136.Final contain null byte, CRLF, and credential injection vulnerabilities in the SOCKS4 (Socks4ClientEncoder) and SOCKS5 (Socks5ClientEncoder) client encoders, which fail to validate domain address and authentication (username/password) fields. An attacker able to control these fields can inject null bytes or CRLF characters to truncate or alter values, potentially enabling domain spoofing, SOCKS4 userid truncation, authentication data injection, and protocol confusion. Fixed in 4.2.17.Final and 4.1.137.Final.

CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-76816

Netty: MQTT Topic Name and Client ID Validation Bypass

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.137.Final and 4.2.17.Final, MqttEncoder does not validate client identifiers, will topics, usernames, and PUBLISH topic names before encoding, allowing prohibited null bytes in MQTT UTF-8 string fields and potentially causing routing, access-control, or identity mismatches in downstream brokers. The vulnerability is exploitable when an application uses Netty's MQTT encoder to construct messages from user-controlled input. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

CVSS 3.1 · 3.5 Low EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2026-62243

Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass

Netty (io.netty:netty-handler) versions from 4.2.0.Final through 4.2.16.Final and versions through 4.1.136.Final disable TLS hostname verification on the SslProvider.OPENSSL client path when a plain (non-extended) X509TrustManager is used and Unsafe-based trust-manager wrapping is unavailable (Java 25+). In this configuration the OpenSSL client does not perform hostname verification, allowing a man-in-the-middle attacker to present a certificate issued for a different hostname that is accepted without validation. Fixed in 4.2.17.Final and 4.1.137.Final.

CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty

CVE-2023-44487

HTTP/2: Multiple HTTP/2 enabled web servers are vulnerable to a DDoS attack (Rapid Reset Attack)

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

CVSS 3.1 · 7.5 High EPSS 100.0% KEV · Listed

Vendors

Akka Amazon Apache and 30 more

Products

Http Server Opensearch Data Prepper Apisix and 375 more

CVE-2026-48748

Netty HTTP/3 QPACK Blocked Streams Memory Exhaustion

Netty is a network application framework for development of protocol servers and clients. Starting in version 4.2.0.Final and prior to version 4.2.15.Final, a memory exhaustion vulnerability in the Netty HTTP/3 codec allows the creation of an infinite number of blocked streams, which can cause OOM error. Version 4.2.15.Final patches the issue.

CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Vendors

Netty

Products

Netty