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.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:2308-1 advisory.

    This update for netty, netty-tcnative fixes the following issues

    - CVE-2026-41417: missing validations leads to HTTP request smuggling and RTSP request injection via     start-line       injection in `DefaultHttpRequest.setUri()` (bsc#1264350).
    - CVE-2026-42578: HTTP Header Injection via HttpProxyHandler Disabled Validation in Netty (bsc#1265243).
    - CVE-2026-42579: DNS codec does not enforce RFC 1035 domain name constraints during either encoding or     decoding       (bsc#1265272).
    - CVE-2026-42580: chunk size parser silently overflows int and enables request smuggling attacks     (bsc#1265273).
    - CVE-2026-42581: TE+CL header coexistence in HTTP/1.0 requests bypasses smuggling sanitization     (bsc#1265277).
    - CVE-2026-42583: resource exhaustion and possible denial of service via `Lz4FrameDecoder` (bsc#1265279).
    - CVE-2026-42584: improper handling of inbound responses in `HttpClientCodec` can lead to response     desynchronization       (bsc#1265280).
    - CVE-2026-42585: Netty is an asynchronous, event-driven network application framework (bsc#1265292).
    - CVE-2026-42586: CRLF Injection in Netty Redis Codec Encoder (bsc#1265245).
    - CVE-2026-42587: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy     enables       decompression bomb DoS (bsc#1265246).
    - CVE-2026-44248: Netty is an asynchronous, event-driven network application framework (bsc#1265294).
    - CVE-2026-42582: HTTP/3 QPACK literal unbounded allocation (bsc#1265318).

    Changes for netty:

    - Upgrade to upstream version 4.1.133

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8401-1 advisory.

    It was discovered that Netty's HTTP proxy handler did not properly validate headers when constructing     CONNECT requests. An attacker could possibly use this issue to inject arbitrary HTTP headers into CONNECT     requests. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS,     and Ubuntu 26.04 LTS. (CVE-2026-42578)

    It was discovered that Netty's DNS codec did not properly enforce domain name constraints. An attacker     could possibly use this issue to bypass domain name validation, or cause Netty to consume resources,     leading to a denial of service. This issue only affected Ubuntu 20.04 LTS, Ubuntu 22.04 LTS, Ubuntu 24.04     LTS, and Ubuntu 26.04 LTS. (CVE-2026-42579)

    It was discovered that Netty did not correctly handle HTTP/1.0 requests containing both a Transfer-     Encoding and Content-Length header. A remote attacker could possibly use this issue to perform HTTP     request smuggling attacks. (CVE-2026-42581)

    Violeta Georgieva discovered that Netty incorrectly paired responses with requests when handling     informational HTTP responses. A remote attacker could possibly use this issue to perform HTTP request     smuggling attacks. (CVE-2026-42584)

    Violeta Georgieva discovered that Netty incorrectly parsed malformed Transfer-Encoding headers. A remote     attacker could possibly use this issue to perform HTTP request smuggling attacks. (CVE-2026-42585)

    It was discovered that Netty's Redis encoder did not validate CRLF characters. An attacker could possibly     use this issue to inject arbitrary Redis commands. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04     LTS, Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 26.04 LTS. (CVE-2026-42586)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2026-42581)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
321020	SUSE SLED15 / SLES15 Security Update : netty, netty-tcnative (SUSE-SU-2026:2308-1)	Nessus	SuSE Local Security Checks	medium
320400	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS : Netty vulnerabilities (USN-8401-1)	Nessus	Ubuntu Local Security Checks	medium
314896	Linux Distros Unpatched Vulnerability : CVE-2026-42581	Nessus	Misc.	critical

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CVE-2026-42581

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