Io.netty:netty codec haproxy: Netty HAProxy: Unbalanced Reference Count in Nested PP2_TYPE_SSL TLV Parsing Leads to Memory Exhaustion (CVE-2026-48059)
### Impact The HAProxy PROXY protocol v2 codec in netty leaks native or heap memory on every connection when a client sends a syntactically valid header containing nested `PP2_TYPE_SSL` TLVs (type-length-value records) at depth two or greater. The leak occurs on the successful parse path — no exception is thrown, the message fires downstream, the decoder removes itself, and the application releases the `HAProxyMessage` normally. Yet the underlying cumulation buffer (a pooled, potentially direct `ByteBuf` allocated by the channel) remains permanently pinned.
AI Analysis
Technical Summary
The HAProxy PROXY protocol v2 codec in the Netty library (io.netty:netty-codec-haproxy) contains a memory leak vulnerability (CVE-2026-48059) triggered by clients sending syntactically valid headers with nested PP2_TYPE_SSL TLVs at depth two or more. The leak happens on the successful parse path without exceptions, where the underlying cumulation buffer remains pinned and is not released, causing native or heap memory exhaustion. This vulnerability affects versions >=4.2.0.Final and <4.2.15.Final, and versions <4.1.135.Final. The CVSS 3.1 score is 7.5 (high severity) with an impact of denial of service via memory exhaustion. Vendor advisories from Red Hat confirm the issue and provide fixed versions in updated builds of Quarkus that upgrade Netty to 4.1.135.Final.
Potential Impact
The vulnerability results in a denial of service condition due to memory exhaustion on the affected system. Memory leaks occur on every connection with crafted nested PP2_TYPE_SSL TLVs, potentially degrading service availability. There is no impact on confidentiality or integrity reported. No known exploits in the wild have been documented at this time.
Mitigation Recommendations
A patch is available and should be applied. Red Hat advisories recommend upgrading to versions of Red Hat build of Quarkus that include Netty 4.1.135.Final or later, which contain the fix for this vulnerability. Users should apply these updates following vendor instructions. No additional mitigation steps are indicated by the vendor advisory.
Io.netty:netty codec haproxy: Netty HAProxy: Unbalanced Reference Count in Nested PP2_TYPE_SSL TLV Parsing Leads to Memory Exhaustion (CVE-2026-48059)
Description
### Impact The HAProxy PROXY protocol v2 codec in netty leaks native or heap memory on every connection when a client sends a syntactically valid header containing nested `PP2_TYPE_SSL` TLVs (type-length-value records) at depth two or greater. The leak occurs on the successful parse path — no exception is thrown, the message fires downstream, the decoder removes itself, and the application releases the `HAProxyMessage` normally. Yet the underlying cumulation buffer (a pooled, potentially direct `ByteBuf` allocated by the channel) remains permanently pinned.
CVSS v3.1
Score 7.5high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The HAProxy PROXY protocol v2 codec in the Netty library (io.netty:netty-codec-haproxy) contains a memory leak vulnerability (CVE-2026-48059) triggered by clients sending syntactically valid headers with nested PP2_TYPE_SSL TLVs at depth two or more. The leak happens on the successful parse path without exceptions, where the underlying cumulation buffer remains pinned and is not released, causing native or heap memory exhaustion. This vulnerability affects versions >=4.2.0.Final and <4.2.15.Final, and versions <4.1.135.Final. The CVSS 3.1 score is 7.5 (high severity) with an impact of denial of service via memory exhaustion. Vendor advisories from Red Hat confirm the issue and provide fixed versions in updated builds of Quarkus that upgrade Netty to 4.1.135.Final.
Potential Impact
The vulnerability results in a denial of service condition due to memory exhaustion on the affected system. Memory leaks occur on every connection with crafted nested PP2_TYPE_SSL TLVs, potentially degrading service availability. There is no impact on confidentiality or integrity reported. No known exploits in the wild have been documented at this time.
Mitigation Recommendations
A patch is available and should be applied. Red Hat advisories recommend upgrading to versions of Red Hat build of Quarkus that include Netty 4.1.135.Final or later, which contain the fix for this vulnerability. Users should apply these updates following vendor instructions. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-h2qv-fj59-j46j
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-48059"]
- Ecosystems
- ["Maven"]
- Database Specific Severity
- HIGH
- Cvss Version
- 4.0
Threat ID: 6a50babc68715ace435869e4
Added to database: 07/10/2026, 09:26:20 UTC
Last enriched: 08/12/2026, 18:02:59 UTC
Last updated: 09/14/2026, 10:01:31 UTC
Views: 103
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