CVE-2026-48059

Netty HAProxy: Unbalanced Reference Count in Nested PP2_TYPE_SSL TLV Parsing Leads to Memory Exhaustion

HIGH
7.5
CVSS Score
Published: June 12, 2026 at 02:42 PM UTC
Updated: September 18, 2026 at 02:29 PM UTC
9 products affected across 2 vendorsNettyBuild of KeycloakFuse

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

Description

Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, 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. Versions 4.1.135.Final and 4.2.15.Final patch the issue.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.1.135v < 4.1.135.Finalv < 4.2.15.Final4.2.0 ≤ v < 4.2.15
Affected range stops below 4.1.135, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.1.135.Final, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.2.15, so it looks safe — our inference, not a vendor statement
Affected range stops below 4.2.15.Final, so it looks safe — our inference, not a vendor statement
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (22)

x_refsource_CONFIRMVendor Advisory
Source: cverecord
https://github.com/netty/netty/security/advisories/GHSA-h2qv-fj59-j46j
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/netty/netty/releases/tag/netty-4.1.135.Final
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/netty/netty/releases/tag/netty-4.2.15.Final
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:26017
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:26018
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/errata/RHSA-2026:26586
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/security/cve/CVE-2026-48059
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://bugzilla.redhat.com/show_bug.cgi?id=2488437

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHredhat-SADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-401CWE-1286

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