CVE-2026-42586 Netty: CRLF Injection in Netty Redis Codec Encoder
Attackers can inject arbitrary Redis commands or forge responses via CRLF injection in the Netty Redis codec encoder.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42586?
CVE-2026-42586 is a medium-severity vulnerability in Netty Netty, published on 13 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the Netty Redis codec encoder (RedisEncoder) writes user-controlled string content directly to the network output buffer without validating or sanitizing CRLF (\r\n) characters. Since the Redis Serialization Protocol (RESP) uses CRLF as the command/response delimiter, an attacker who can control the content of a Redis message can inject arbitrary Redis commands or forge fake responses. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
Weakness: CWE-93
Which versions are affected by CVE-2026-42586?
4 open source packages ship an affected version, including io.netty:netty-codec-redis. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
io.netty:netty-codec-redis Maven | All versions | 4.1.133.Final |
io.netty:netty-codec-redis Maven | All versions | 4.1.133.Final |
io.netty:netty-codec-redis Maven | From 4.2.0.Alpha1 | 4.2.13.Final |
io.netty:netty-codec-redis Maven | From 4.2.0.Alpha1 | 4.2.13.Final |
Products include Netty Netty.
How do I fix CVE-2026-42586?
Upgrade io.netty:netty-codec-redis to a fixed version for your release line: 4.1.133.Final or 4.2.13.Final.
Is CVE-2026-42586 being exploited?
There is no known exploitation of CVE-2026-42586 in the wild and no public exploit code.
Other vulnerabilities in Netty Netty
- CVE-2026-75595 Netty: SNI Routing Bypass via Fragmented TLS ClientHello Causing Fallback to Default SslContext
- CVE-2026-75596 Netty: Fragmented ClientHello records trigger quadratic pre-handshake reassembly in default SNI parsing
- CVE-2026-59901 Netty Bzip2Decoder: Infinite Loop in RLE State Machine Leads to Event-Loop Thread Hang
- CVE-2026-55851 Netty codec-haproxy: Signed-Byte Sentinel Collision in HAProxyMessageDecoder Leads to Unbounded Memory Exhaustion
- CVE-2026-56745 Netty SpdyHttpDecoder: ByteBuf Reference Leak on RST_STREAM Leads to Native Memory Exhaustion
Sources
Also known as CLEANSTART-2026-BS28431, CLEANSTART-2026-LT22679, CLEANSTART-2026-TD23067, CLSA-2026-1788193874, CLSA-2026-1788418779, DEBIAN-CVE-2026-42586 and 6 more.