Io.netty:netty codec http2: netty-codec-http2: ByteBuf Reference-Count Leak in DelegatingDecompressorFrameListener Leads to Memory Exhaustion (CVE-2026-48043)
### Impact The `DelegatingDecompressorFrameListener` class orchestrates HTTP/2 decompression by embedding a per-stream `EmbeddedChannel` that runs the appropriate decompression codec (gzip, deflate, zstd) and forwards decompressed chunks to a wrapped listener. Each decompressed chunk is a pooled `ByteBuf` handed to an anonymous `ChannelInboundHandlerAdapter` tail handler, which becomes the sole owner responsible for releasing it. A remote peer could send frames that would result in the flow-controller throwing and so trigger a resource leak which at the end might take down the whole JVM due OOME.
AI Analysis
Technical Summary
The DelegatingDecompressorFrameListener class in netty-codec-http2 manages HTTP/2 decompression by using an EmbeddedChannel per stream to run decompression codecs and forward decompressed ByteBuf chunks to a listener. A flaw in this process allows a remote peer to send frames that cause the flow-controller to throw, resulting in a ByteBuf reference-count leak. This leak can accumulate, leading to memory exhaustion and potentially crashing the JVM with an OutOfMemoryError. The vulnerability is tracked as CVE-2026-48043 and has been addressed in updated versions of Red Hat's build of Quarkus by upgrading Netty to version 4.1.135.Final.
Potential Impact
The vulnerability causes a denial of service through memory exhaustion in applications using netty-codec-http2 for HTTP/2 decompression. Specifically, it can lead to an OutOfMemoryError and JVM crash due to a ByteBuf reference-count leak triggered by maliciously crafted HTTP/2 frames. There is no direct impact on confidentiality or integrity reported, only availability is affected.
Mitigation Recommendations
Red Hat has released security updates for their build of Quarkus (versions 3.27.4.SP1 and 3.33.2.SP1) that include an upgrade of Netty to version 4.1.135.Final, which contains the fix for this vulnerability. Users should apply these official updates to remediate the issue. No other mitigation or workaround is indicated in the vendor advisories.
Io.netty:netty codec http2: netty-codec-http2: ByteBuf Reference-Count Leak in DelegatingDecompressorFrameListener Leads to Memory Exhaustion (CVE-2026-48043)
Description
### Impact The `DelegatingDecompressorFrameListener` class orchestrates HTTP/2 decompression by embedding a per-stream `EmbeddedChannel` that runs the appropriate decompression codec (gzip, deflate, zstd) and forwards decompressed chunks to a wrapped listener. Each decompressed chunk is a pooled `ByteBuf` handed to an anonymous `ChannelInboundHandlerAdapter` tail handler, which becomes the sole owner responsible for releasing it. A remote peer could send frames that would result in the flow-controller throwing and so trigger a resource leak which at the end might take down the whole JVM due OOME.
CVSS v3.1
Score 5.3medium
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The DelegatingDecompressorFrameListener class in netty-codec-http2 manages HTTP/2 decompression by using an EmbeddedChannel per stream to run decompression codecs and forward decompressed ByteBuf chunks to a listener. A flaw in this process allows a remote peer to send frames that cause the flow-controller to throw, resulting in a ByteBuf reference-count leak. This leak can accumulate, leading to memory exhaustion and potentially crashing the JVM with an OutOfMemoryError. The vulnerability is tracked as CVE-2026-48043 and has been addressed in updated versions of Red Hat's build of Quarkus by upgrading Netty to version 4.1.135.Final.
Potential Impact
The vulnerability causes a denial of service through memory exhaustion in applications using netty-codec-http2 for HTTP/2 decompression. Specifically, it can lead to an OutOfMemoryError and JVM crash due to a ByteBuf reference-count leak triggered by maliciously crafted HTTP/2 frames. There is no direct impact on confidentiality or integrity reported, only availability is affected.
Mitigation Recommendations
Red Hat has released security updates for their build of Quarkus (versions 3.27.4.SP1 and 3.33.2.SP1) that include an upgrade of Netty to version 4.1.135.Final, which contains the fix for this vulnerability. Users should apply these official updates to remediate the issue. No other mitigation or workaround is indicated in the vendor advisories.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-c2gf-v879-257j
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-48043"]
- Ecosystems
- ["Maven"]
- Database Specific Severity
- MODERATE
- Cvss Version
- 3.1
Threat ID: 6a50babc68715ace43586a1f
Added to database: 07/10/2026, 09:26:20 UTC
Last enriched: 07/10/2026, 10:20:55 UTC
Last updated: 07/31/2026, 20:04:43 UTC
Views: 55
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