High 8.7Published Jul 21, 2026

CVE-2026-56745Netty SpdyHttpDecoder: ByteBuf Reference Leak on RST_STREAM Leads to Native Memory Exhaustion

Updated under an hour ago (Oct 27, 2026, 6:40 AM ET)

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Exploited in the last 30 days

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and 4.1.0.Final through 4.1.135.Final, the `SpdyHttpDecoder` handler in Netty's SPDY-to-HTTP codec allocates a pooled `ByteBuf` when processing a client-initiated `SYN_STREAM` frame with `FLAG_FIN=0` and stores the partially constructed `FullHttpRequest` in `messageMap`; when the remote peer sends `RST_STREAM` for that stream or the accumulated content exceeds `maxContentLength`, the decoder removes the entry but does not release the pooled `ByteBuf`, causing native memory exhaustion. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

CVSS: 8.7 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness (CWE): CWE-400
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 22, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

netty netty netty:netty (from the name)	from 4.2.0.Final, < 4.2.16.Final; from 4.1.0.Final, < 4.1.136.Final	CNA record
netty netty netty:netty	from 4.1.0 before 4.1.136; from 4.2.0 before 4.2.16	NVD

References

References

https://github.com/netty/netty/security/advisories/GHSA-jppx-w49h-x2qq	x-refsource-confirm, vendor-advisory
https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b	x-refsource-misc, patch
https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6	x-refsource-misc, patch
https://github.com/netty/netty/releases/tag/netty-4.1.136.Final	x-refsource-misc, release-notes
https://github.com/netty/netty/releases/tag/netty-4.2.16.Final	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.