Vulnerability Description
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer size and prevent decompression bomb attacks. This limit is correctly enforced for gzip and deflate encodings via ZlibDecoder, but is silently ignored when the content encoding is br (Brotli), zstd, or snappy. An attacker can bypass the configured decompression limit by sending a compressed payload with Content-Encoding: br instead of Content-Encoding: gzip, causing unbounded memory allocation and out-of-memory denial of service. The same vulnerability exists in DelegatingDecompressorFrameListener for HTTP/2 connections. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Netty | Netty | < 4.1.133 |
Related Weaknesses (CWE)
References
- https://github.com/netty/netty/security/advisories/GHSA-f6hv-jmp6-3vwvExploitMitigationVendor Advisory
- https://github.com/netty/netty/security/advisories/GHSA-f6hv-jmp6-3vwvExploitMitigationVendor Advisory
FAQ
What is CVE-2026-42587?
CVE-2026-42587 is a vulnerability with a CVSS score of 7.5 (HIGH). Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpContentDecompressor accepts a maxAllocation parameter to limit decompression buffer s...
How severe is CVE-2026-42587?
CVE-2026-42587 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-42587?
Check the references section above for vendor advisories and patch information. Affected products include: Netty Netty.