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netty vulnerabilities

Vulnerabilities published for netty in the last 30 days: 4. Listed in the KEV catalogue: 0.

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Vulnerabilities: 119

  1. CVE-2026-100666

    Medium · CVSS 6.9EPSS 0.24%No fix published

    Netty 4.2.0 through 4.2.16 Response Desynchronization via HttpServerCodec

    Netty's HttpServerCodec (io.netty:netty-codec-http) in versions 4.2.0.Final through 4.2.16.Final and in versions up to and including 4.1.136.Final pairs each outbound response with an inbound request by calling pollMethod() once per response, including for 1xx informational responses. If a client pipelines an HTTP/1.1 GET carrying an Expect: 100-continue header followed by a HEAD request, the 100 Continue response consumes the queued GET method, so the subsequent 200 OK for the GET is paired with HEAD and its body is dropped, while the following 200 OK for the HEAD request is written with a body. This desynchronizes HTTP parsing on the connec

    Published Updated
  2. CVE-2026-93562

    Medium · CVSS 6.5EPSS 0.41%No fix published

    Io.netty/netty-codec-http: netty: incomplete validation of malformed transfer-encoding allows http request smuggling

    A flaw was found in Netty's HTTP/1 decoder. Incomplete validation of malformed Transfer-Encoding headers allows a remote attacker to perform HTTP request smuggling. By sending specially crafted HTTP requests, an attacker can inject arbitrary HTTP requests, potentially bypassing security controls or accessing unauthorized resources.

    Published Updated
  3. CVE-2026-93574

    Medium · CVSS 6.5EPSS 1.35%No fix published

    Io.netty/netty-codec-http: netty: http request smuggling via post-digit whitespace in chunk-size parsing

    A flaw was found in Netty's `netty-codec-http` component. A remote attacker could exploit this vulnerability by sending a specially crafted HTTP/1.1 chunk-size token that includes post-digit whitespace. This incorrect parsing of the chunk size can lead to HTTP request smuggling. This allows an attacker to bypass security controls or access unauthorized resources in proxy/backend deployments.

    Published Updated
  4. CVE-2026-93579

    Medium · CVSS 6.5EPSS 0.9%No fix published

    Io.netty/netty-codec-http2: netty: http/2 header field values are not validated by default (cr/lf/nul passthrough)

    A flaw was found in Netty's HTTP/2 stack. This vulnerability allows a remote attacker to inject prohibited characters, such as NUL, Line Feed, and Carriage Return, into HTTP/2 header field values due to insufficient validation. When these values cross an HTTP/2 to HTTP/1.1 translation boundary, they can be exploited for request smuggling, header injection, or response splitting. This could lead to unauthorized access, data manipulation, or other security bypasses.

    Published Updated
  5. CVE-2026-93573

    Medium · CVSS 6.5EPSS 0.9%No fix published

    Io.netty/netty-codec-http: netty split transfer-encoding fields bypass final-chunked validation and enable request smuggling

    A flaw was found in Netty's HTTP/1.1 decoder. This vulnerability allows a remote attacker to bypass `Transfer-Encoding` header validation by splitting the `Transfer-Encoding` field across multiple headers, with the last field containing a non-final transfer coding like `gzip` or `deflate`. This bypass can lead to HTTP request smuggling, enabling attackers to bypass security controls, desynchronize request processing, or cause requests to be processed in an unintended context.

    Published Updated
  6. CVE-2026-93568

    High · CVSS 7.5EPSS 0.95%No fix published

    Io.netty/netty-codec-http2: io.netty/netty-codec-http3: netty: http/2 and http/3 extended connect requests are downgraded as regular connect requests

    A flaw was found in Netty. A remote attacker could exploit this vulnerability by sending specially crafted HTTP/2 or HTTP/3 Extended CONNECT requests. Netty's HTTP-object conversion path incorrectly processes these requests as regular HTTP/1.1 CONNECT requests, leading to a loss of critical protocol and path information. This misinterpretation can allow attackers to bypass security policies, such as routing or authorization logic, in applications that rely on Netty for HTTP/2 or HTTP/3 communication, resulting in integrity loss.

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  7. CVE-2026-93576

    High · CVSS 7.5EPSS 0.27%No fix published

    Io.netty/netty-codec-smtp: netty netty-codec-smtp — smtp command-name field is not crlf-validated (incomplete fix of cve-2025-59419)

    A flaw was found in Netty netty-codec-smtp. The component does not properly validate Carriage Return (CR) and Line Feed (LF) characters in the SMTP command-name field. A remote attacker, if an application routes untrusted input into this field, can embed CR/LF characters to inject arbitrary SMTP commands. This can lead to SMTP command smuggling, allowing for unauthorized email relay or spoofing of sender/recipient addresses. While the impact is significant, the real-world exploitability is considered lower as applications typically do not place user-controlled data in the command-name field.

    Published Updated
  8. CVE-2026-93569

    High · CVSS 8.2EPSS 2.19%No fix published

    Io.netty/netty-codec-http2: http/1 absolute-form host mismatch is translated to http/2 :authority, overriding the request-target authority

    A flaw was found in Netty. A remote unauthenticated attacker can exploit a vulnerability in Netty's HTTP/1 to HTTP/2 conversion process. When an HTTP/1 request includes both an absolute-form request-target and a conflicting Host header, Netty incorrectly prioritizes the Host header for the HTTP/2 :authority field, discarding the original request-target authority. This inconsistency can allow an attacker to bypass security controls in Netty-based proxies or gateways, potentially leading to unauthorized access, cache poisoning, or misrouting of requests.

    Published Updated
  9. CVE-2026-93567

    High · CVSS 7.5EPSS 2.56%No fix published

    Io.netty/netty-codec-http2: http/1 authority-form connect is translated to malformed http/2 connect with host-controlled :authority

    A flaw was found in Netty's HTTP/2 codec. When converting HTTP/1 CONNECT requests to HTTP/2, the component incorrectly uses the Host header instead of the CONNECT authority-form request-target for the tunnel authority. A remote attacker can exploit this by supplying a different Host header, leading to a malformed HTTP/2 CONNECT request. This can bypass security controls such as tunnel allow-lists or egress policies, resulting in integrity loss.

    Published Updated
  10. CVE-2026-93566

    Medium · CVSS 6.5EPSS 0.48%No fix published

    Io.netty/netty-codec-http: netty: http request smuggling due to control characters in the chunk-size line

    A flaw was found in Netty. A remote attacker could exploit this by sending a specially crafted HTTP request that includes control characters within the chunk-size line. This bypasses the intended strict validation, allowing the attacker to inject arbitrary HTTP requests. This vulnerability can lead to HTTP request smuggling, potentially resulting in information disclosure or other unauthorized actions.

    Published Updated
  11. CVE-2026-93565

    High · CVSS 7.5EPSS 0.77%No fix published

    Io.netty/netty-codec-http: netty rtspdecoder method-token smuggling via trailing control byte

    A flaw was found in Netty RtspDecoder. The `RtspMethods.valueOf()` function incorrectly strips trailing control bytes from method tokens in Real-Time Streaming Protocol (RTSP) requests. A remote attacker can exploit this by sending a specially crafted RTSP request, leading to method-token smuggling. This vulnerability allows an attacker to bypass method-based access controls and can also be used to launder malicious requests through Netty-based RTSP proxies, making them appear legitimate to backend systems.

    Published Updated
  12. CVE-2026-93564

    High · CVSS 7.5EPSS 0.94%No fix published

    Io.netty/netty-codec-haproxy: netty: haproxy proxy-v2 nested-tlv grandchild bytebuf reference-count leak (incomplete fix of pr #16881)

    A flaw was found in Netty. A reference-count leak in the HAProxy PROXY-v2 message decoder allows a remote, unauthenticated attacker to send specially crafted PROXY-protocol v2 headers. This can lead to memory exhaustion, resulting in a Denial of Service (DoS) for the affected system.

    Published Updated
  13. CVE-2026-93558

    High · CVSS 7.5EPSS 1.08%No fix published

    Io.netty/netty-codec-http: netty: unbounded per-connection queue growth in websocketserverextensionhandler leads to denial of service

    A flaw was found in Netty's WebSocketServerExtensionHandler. A remote, unauthenticated attacker can exploit this vulnerability by using HTTP/1.1 pipelining to send requests faster than the application can respond. This leads to an unbounded growth of a per-connection queue, consuming excessive memory. Eventually, this can cause the Java Virtual Machine (JVM) to exhaust its heap, resulting in a Denial of Service (DoS) for the affected server.

    Published Updated
  14. CVE-2026-93560

    High · CVSS 7.5EPSS 0.41%No fix published

    Io.netty/netty-codec-stomp: netty: stomp codec content-length long-to-int truncation causes infinite decode loop dos

    A flaw was found in the Netty STOMP codec. A remote attacker could send a specially crafted STOMP frame with a content-length header exceeding the maximum integer value. This integer truncation vulnerability could lead to an infinite decode loop, causing a Denial of Service (DoS) by exhausting memory and CPU resources.

    Published Updated
  15. CVE-2026-93492

    Medium · CVSS 5.3EPSS 0.37%No fix published

    Io.netty/netty-codec-http2: netty: http/2 hpackencoder dos with large table size

    A flaw was found in Netty's HTTP/2 HpackEncoder. A remote attacker can exploit this by sending HTTP/2 SETTINGS frames with a very large MAX_HEADER_TABLE_SIZE. This causes the HpackEncoder to store an excessive number of unique headers, leading to increased CPU usage and memory consumption, ultimately resulting in a Denial of Service (DoS).

    Published Updated
  16. CVE-2026-93491

    High · CVSS 7.5EPSS 0.73%No fix published

    Io.netty/netty-codec-http: netty: denial of service via unbounded httpservercodec http/1.1 pipeline queue

    A flaw was found in Netty's HttpServerCodec. A remote, unauthenticated attacker can exploit this vulnerability by pipelining HTTP/1.1 requests on a single connection and withholding reads. This action causes the methodOverflowQueue to grow without limit, leading to unbounded heap memory consumption and a denial of service due to memory exhaustion.

    Published Updated
  17. CVE-2026-93488

    High · CVSS 7.5EPSS 0.8%No fix published

    Io.netty/netty-codec-http: netty: denial of service via unbounded concurrent spdy streams

    A flaw was found in Netty. SpdySessionHandler accepts an unlimited number of concurrent remote-initiated streams because localConcurrentStreams defaults to Integer.MAX_VALUE and the handler provides no API to change it. A remote peer can open a SPDY connection and send a large number of SYN_STREAM frames with FLAG_FIN=0, causing unbounded heap and direct memory allocation that can lead to JVM OutOfMemoryError and a denial of service.

    Published Updated

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