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, before reading the first request-line, `HttpObjectDecoder` skips every byte for which `Character.isISOControl(b)` is `true` (0x00–0x1F and 0x7F) as well as all whitespace. RFC 9112 §2.2 only asks servers to ignore empty CRLF lines preceding the request-line — a carefully scoped robustness allowance intended to handle HTTP/1.0 POST workarounds. Silently absorbing NUL bytes, SOH, STX, and other non-CRLF control characters goes significantly beyond this, and can be exploited for request-boundary confusion in pipelined or multiplexed transports where a front-end component treats those bytes differently. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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, before reading the first request-line, `HttpObjectDecoder` skips
    every byte for which `Character.isISOControl(b)` is `true` (0x00–0x1F and 0x7F) as well as all whitespace.
    RFC 9112 §2.2 only asks servers to ignore empty CRLF lines preceding the request-line — a carefully scoped
    robustness allowance intended to handle HTTP/1.0 POST workarounds. Silently absorbing NUL bytes, SOH, STX,
    and other non-CRLF control characters goes significantly beyond this, and can be exploited for request-
    boundary confusion in pipelined or multiplexed transports where a front-end component treats those bytes
    differently. Versions 4.1.135.Final and 4.2.15.Final patch the issue. (CVE-2026-50020)

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-2026:2802-1 advisory.

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

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

    Upgrade netty to upstream version 4.1.135, netty-tcnative to upstream version 2.0.79:

    - CVE-2026-44249: IPv6 Subnet Filter Bypass via Incorrect Comparator Masking (bsc#1268165).
    - CVE-2026-44250: Memory Exhaustion in RedisArrayAggregator due to Deeply Nested Arrays (bsc#1268169).
    - CVE-2026-44890: Unbounded Direct Memory Consumption in RedisDecoder (bsc#1268170).
    - CVE-2026-44893: netty-codec-haproxy: Denial of Service via malformed HAProxy message (bsc#1268244).
    - CVE-2026-45416: SNI handler pre-allocates up to 16 MiB from nine attacker bytes (bsc#1268246).
    - CVE-2026-45536: Unix-socket fd receive leaks descriptors when peer sends two at once (bsc#1268247).
    - CVE-2026-45673: netty-resolver-dns: DNS Cache Poisoning via predictable transaction IDs (bsc#1268248).
    - CVE-2026-45674: DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records (bsc#1268249).
    - CVE-2026-46340: netty-transport-sctp: Denial of Service due to unbounded memory growth from SctpMessage     fragments       (bsc#1268250).
    - CVE-2026-47244: HTTP/2: Advertised MAX_CONCURRENT_STREAMS not enforced (bsc#1268251).
    - CVE-2026-47691: Insufficient Bailiwick Validation for NS Records (bsc#1268252).
    - CVE-2026-48006: netty-codec-redis: Netty's Lack of Lifecycle Cleanup Leads to Pooled ByteBuf Leak in       RedisArrayAggregator (bsc#1268255).
    - CVE-2026-48043: netty-codec-http2: Denial of Service due to resource leak (bsc#1268257).
    - CVE-2026-48059: netty-codec-haproxy: Denial of Service via memory leak from crafted PROXY protocol     headers       (bsc#1268258).
    - CVE-2026-50010: Wrapping plain trust manager silently disables hostname verification (bsc#1268259).
    - CVE-2026-50011: Unbounded pre-allocation in RedisArrayAggregator from RESP array length (bsc#1268260).
    - CVE-2026-50020: HttpObjectDecoder skips arbitrary initial control characters when only initial CRLF     characters are       permitted (bsc#1268261).
    - CVE-2026-50560: Netty susceptible to HTTP/2 Reset Attack with different on-the-wire signature     (bsc#1268262).

    Changes:

     - MQTT: Allow MQTT 5 CONNECT with password only      + ChannelInitializer: correct misleading comment on      exceptionCaught route      + HTTP/2: Parse request-target path like Vert.x (4.1 backport)      + HttpObjectDecoder skips arbitrary initial control characters      when only initial CRLF characters are permitted      + IpSubnetFilter: Correctly handle ipv6      + Configurable bound on RedisArrayAggregator      + Redis: Limit decoded length      + DNS: Ensure query id is not predictible      + Wrapping plain trust manager silently disables hostname      verification      + MQTT: Reject malformed no-payload packets with non-zero      Remaining Length      + HAProxy: Reject HAProxyMessages with malformated TLV and not      leak memory      + SSL: Use sane defaults as limits for the client hello length      and timeout      + DNS: Only cache CNAME if part of the queried domain      + HTTP/2: Enforce max concurrent streams for misbehaving clients      + Dns: Insufficient Bailiwick Validation for NS Records      + HTTP2: DelegatingDecompressorFrameListener must release memory      in all cases      + Pass maxAllocation to Brotli and Zstd decoders      + HTTP/2: Treat clients MAX_HEADER_LIST_SIZE as advisory      + Add maxWindowLog parameter to ZstdDecoder to bound memory      allocation      + HAProxy: Fix ByteBuf leak when parsing nested SSL TLVs      + Epoll / Kqueue: Correctly handle receive of FD      + SCTP: Limit the number of inflight incomplete SCTP messages      and the number of fragments      + Redis: Correctly release incomplete message on removal when      using RedisArrayAggregator      + Redis: Limit the maximum number of nested arrays      + HTTP: Re-add constructor to HttpProxyHandler that was removed      by mistake      + Marshalling: Explicit document security requirements      + Pin HTTP/RTSP version + method normalization to Locale.US      + Adaptive: Fix concurrency issue in adaptive allocator      + Pin multipart Content-Type / Content-Transfer-Encoding case      folding to Locale.US      + Remove dead native declarations      + Avoid re-parsing openssl key material with non-cached provider      + IpFilter: Fix ClassCastException caused by IpSubnetFilter if      only ipv6 rules are configured but remote peer is using ipv4      + Resolve all localhost addresses without querying DNS servers      + HTTP2: Use 100 as default max concurrent streams setting      + Route synchronous onLookupComplete exceptions via      fireExceptionCaught      + Fix MQTT decoder size check after variable header replay

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

  - 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, before reading the first request-line, `HttpObjectDecoder` skips     every byte for which `Character.isISOControl(b)` is `true` (0x000x1F and 0x7F) as well as all whitespace.
    RFC 9112 2.2 only asks servers to ignore empty CRLF lines preceding the request-line  a carefully scoped     robustness allowance intended to handle HTTP/1.0 POST workarounds. Silently absorbing NUL bytes, SOH, STX,     and other non-CRLF control characters goes significantly beyond this, and can be exploited for request-     boundary confusion in pipelined or multiplexed transports where a front-end component treats those bytes     differently. Versions 4.1.135.Final and 4.2.15.Final patch the issue. (CVE-2026-50020)

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

ID	Name	Product	Family	Type	Severity
459530	Echo: io.netty:netty-codec-http: security update to 4.1.135.Final	Tenable Cloud Security	Echo Local Security Checks	Local	medium
459530	Echo: io.netty:netty-codec-http: security update to 4.1.135.Final	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	medium
326003	SUSE SLED15 / SLES15 Security Update : netty, netty-tcnative (SUSE-SU-2026:2802-1)	Nessus	SuSE Local Security Checks	Local	high
443219	SCA: security update for io.netty:netty-codec-http (GHSA-hvcg-qmg6-jm4c)	Tenable Cloud Security	SCA Checks	Local	medium
443219	SCA: security update for io.netty:netty-codec-http (GHSA-hvcg-qmg6-jm4c)	Tenable Self-Hosted Container Security	SCA Checks	Local	medium
320919	Linux Distros Unpatched Vulnerability : CVE-2026-50020	Nessus	Misc.	Local	medium

Detections

Analytics

CVE-2026-50020

medium

Tenable Plugins

medium

medium

high

medium

medium

medium