What’s Vulnerable › Vulnerabilities

CVE-2026-42586: Netty: CRLF Injection in Netty Redis Codec Encoder

• Severity: high (CVSS 7.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-13 · updated 2026-10-26
• Weakness: CWE-93

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.

Affected products

• netty: before 4.1.133; from 4.2.0 before 4.2.13 — fixed in 4.1.133, 4.2.13

How to fix

Upgrade to a fixed version: netty 4.1.133, 4.2.13. Check the vendor advisory for mitigations.

References

• https://github.com/netty/netty/security/advisories/GHSA-rgrr-p7gp-5xj7
• https://github.com/netty/netty/security/advisories/GHSA-rgrr-p7gp-5xj7

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