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CVE-2026-93564· NVD / CVE Program· CNA redhat

Io.netty/netty-codec-haproxy: netty: haproxy proxy-v2 nested-tlv grandchild bytebuf reference-count leak (incomplete fix of pr #16881)

A flaw was found in Netty. A reference-count leak in the HAProxy PROXY-v2 message decoder allows a remote, unauthenticated attacker to send specially crafted PROXY-protocol v2 headers. This can lead to memory exhaustion, resulting in a Denial of Service (DoS) for the affected system.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Sep 18, 2026
Updated
Sep 22, 2026
EPSS
0.8% · 55th percentile
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Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
7.5
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Red Hat Red Hat AMQ Broker 7

    • all versionsaffected

  • Red Hat Red Hat build of Apache Camel 4 for Quarkus 3

    • all versionsaffected

  • Red Hat Red Hat build of Apache Camel for Spring Boot 4

    • all versionsaffected

  • Red Hat Red Hat build of Apicurio Registry 3

    • all versionsaffected

  • Red Hat Red Hat build of Debezium 3

    • all versionsaffected

  • Red Hat Red Hat Build of Keycloak

    • all versionsaffected

  • Red Hat Red Hat Fuse 7

    • all versionsaffected

  • Red Hat Red Hat JBoss Enterprise Application Platform 7

    • all versionsaffected

  • Red Hat Red Hat Single Sign-On 7

    • all versionsaffected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12nettyall versions—
openSUSE:Tumbleweednettybefore 4.1.138-1.14.1.138-1.1

Same product

red hat: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-101292Artemis-core-client: unsafe reflection in apache activemq artemis federation message deserialization
    32Monitor
  • CVE-2026-93569Io.netty/netty-codec-http2: http/1 absolute-form host mismatch is translated to http/2 :authority, overriding the request-target authority
    32Monitor
  • CVE-2026-84218Org.jolokia/jolokia-core: incomplete jndi denylist in jolokia jsr-160 proxy (bypass of cve-2018-1000130 fix)
    32Monitor
  • CVE-2026-93568Io.netty/netty-codec-http2: io.netty/netty-codec-http3: netty: http/2 and http/3 extended connect requests are downgraded as regular connect requests
    30Monitor
  • CVE-2026-93567Io.netty/netty-codec-http2: http/1 authority-form connect is translated to malformed http/2 connect with host-controlled :authority
    30Monitor
  • CVE-2026-93565Io.netty/netty-codec-http: netty rtspdecoder method-token smuggling via trailing control byte
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
opensuse:netty4.1.138-1.1 · openSUSE:TumbleweedPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-935580 days apartIo.netty/netty-codec-http: netty: unbounded per-connection queue growth in websocketserverextensionhandler leads to denial of service
    30Monitor
  • CVE-2026-935650 days apartIo.netty/netty-codec-http: netty rtspdecoder method-token smuggling via trailing control byte
    30Monitor
  • CVE-2026-935750 days apartIo.netty/netty-codec-mqtt: netty: resource exhaustion in mqttdecoder
    30Monitor
  • CVE-2026-935620 days apartIo.netty/netty-codec-http: netty: incomplete validation of malformed transfer-encoding allows http request smuggling
    26Monitor
  • CVE-2026-935660 days apartIo.netty/netty-codec-http: netty: http request smuggling due to control characters in the chunk-size line
    26Monitor
  • CVE-2026-935790 days apartIo.netty/netty-codec-http2: netty: http/2 header field values are not validated by default (cr/lf/nul passthrough)
    26Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-1035 · OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records