Netty: [SpdyHttpDecoder] ByteBuf Reference Leak on RST_STREAM Leads to Native Memory Exhaustion
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, storing the partially-constructed FullHttpRequest in an internal map (messageMap) to accumulate subsequent DATA frames. When the remote peer sends an RST_STREAM for that stream, or when the accumulated content exceeds maxContentLength, the decoder removes the entry from the map but never releases the pooled ByteBuf, permanently leaking the allocated memory.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | io.netty:netty-codec-http | >= 4.2.0.Final, < 4.2.16.Final, >= 4.1.0.Final, < 4.1.136.Final | 4.2.16.Final, 4.1.136.Final |
References
- https://github.com/netty/netty/security/advisories/GHSA-jppx-w49h-x2qq
- https://nvd.nist.gov/vuln/detail/CVE-2026-56745
- https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b
- https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6
- https://github.com/netty/netty
- https://github.com/netty/netty/releases/tag/netty-4.1.136.Final
- https://github.com/netty/netty/releases/tag/netty-4.2.16.Final
- CVSS vector
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- Platform
- Java / Kotlin (Maven)
- Package
io.netty:netty-codec-http- Disclosed
- 22.07.2026
- Updated
- 11.10.2026 13:20
Sources and licenses
OSV / GitHub Advisory Database - GHSA-jppx-w49h-x2qq - CC BY 4.0
Vulnerability history: io.netty:netty-codec-http
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 24
- First → latest
- 02.2020 08.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 6
- Medium 16
- Low 1
Disclosures per year
- 2020: 1
- 2021: 2
- 2022: 2
- 2023: 0
- 2024: 1
- 2025: 2
- 2026: 16
-
Netty: [SpdyHttpDecoder] ByteBuf Reference Leak on RST_STREAM Leads to Native Memory Exhaustion this entry
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