CVE-2026-45416: Netty: SNI handler pre-allocates up to 16 MiB from nine attacker bytes
Noroxi assessment
Priority: Monitor (action score 30/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.92% (FIRST EPSS); higher than 60.7% of all records.
- 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.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: io.netty:netty-handler (Maven) 4.2.15.Final, 4.1.135.Final; netty (openSUSE:Tumbleweed) 4.1.135-1.1; eap8-eap-product-conf-parent (Red Hat:jboss_enterprise_application_platform:8.1::el10) 0:801.7.1-1.GA_redhat_00001.1.el10eap.
Low priority for now. Upgrade to io.netty:netty-handler (Maven) 4.2.15.Final, 4.1.135.Final; netty (openSUSE:Tumbleweed) 4.1.135-1.1; eap8-eap-product-conf-parent (Red Hat:jboss_enterprise_application_platform:8.1::el10) 0:801.7.1-1.GA_redhat_00001.1.el10eap or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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, SslClientHelloHandler.decode() reads the 24-bit TLS handshake length and, when the ClientHello does not fit in the first record, eagerly allocates `ctx.alloc().buffer(handshakeLength)` (line 161). The guard at line 140 is `handshakeLength > maxClientHelloLength && maxClientHelloLength != 0`, and the commonly-used SniHandler/AbstractSniHandler constructors (SniHandler(Mapping), SniHandler(AsyncMapping), AbstractSniHandler()) pass maxClientHelloLength=0 and handshakeTimeoutMillis=0, so the length guard is disabled and no timeout is scheduled. A 16 MiB request exceeds the default pooled chunk size and becomes a huge/unpooled allocation performed immediately. The buffer is retained in the handler until the channel closes. Versions 4.1.135.Final and 4.2.15.Final patch the issue.
- Published
- Jun 12, 2026
- Updated
- Sep 18, 2026
- EPSS
- 0.9% · 60th percentile
- CWE
- CWE-770
Report tools
Action score
30
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.9%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 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.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| netty | netty | cpe:2.3:a:netty:netty |
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
netty netty
- >= 4.2.0.Final, < 4.2.15.Final, < 4.1.135.Finalaffected
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- netty nettybefore 4.1.135
- netty netty4.2.0 and later · before 4.2.15
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | netty | from 0 | — |
| Maven | io.netty:netty-handler | from 4.2.0.Final · before 4.2.15.Final | 4.2.15.Final |
| Maven | io.netty:netty-handler | before 4.1.135.Final | 4.1.135.Final |
| openSUSE:Tumbleweed | netty | before 4.1.135-1.1 | 4.1.135-1.1 |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-eap-product-conf-parent | before 0:801.7.1-1.GA_redhat_00001.1.el10eap | 0:801.7.1-1.GA_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-eap-product-conf-wildfly-ee-feature-pack | before 0:801.7.1-1.GA_redhat_00001.1.el10eap | 0:801.7.1-1.GA_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-buffer | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-codec | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-codec-dns | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-codec-http | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-codec-socks | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-common | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-handler | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-handler-proxy | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-resolver | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-resolver-dns | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-transport | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-transport-classes-epoll | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-transport-native-epoll | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-transport-native-epoll-debuginfo | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-netty-transport-native-unix-common | before 0:4.1.135-1.Final_redhat_00001.1.el10eap | 0:4.1.135-1.Final_redhat_00001.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-wildfly | before 0:8.1.7.1-1.GA_redhat_00004.1.el10eap | 0:8.1.7.1-1.GA_redhat_00004.1.el10eap |
| Red Hat:jboss_enterprise_application_platform:8.1::el10 | eap8-wildfly-java-jdk21 | before 0:8.1.7.1-1.GA_redhat_00004.1.el10eap | 0:8.1.7.1-1.GA_redhat_00004.1.el10eap |
+55
Same product
netty: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-47691Netty has Insufficient Bailiwick Validation for NS Records40Plan
- CVE-2026-45674Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records40Plan
- CVE-2019-20445HttpObjectDecoder.java in Netty before 4.1.44 allows a Content-Length header to be accompanied by a second Content-Length header, or by a…40Plan
Published before and after this one in the same product
- ← EarlierCVE-2026-44893Jun 12, 2026 · Netty: HAProxy SSL TLV parsing leaks retained slice on invalid TLV length30Monitor
- ← EarlierCVE-2026-44894Jun 12, 2026 · Netty's Default QUIC token handler accepts any client-supplied token30Monitor
- Later →CVE-2026-45536Jun 12, 2026 · Netty: Unix-socket fd receive leaks descriptors when peer sends two at once16Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Maven:io.netty:netty-handler | 4.1.135.Final | Package registry (OSV) |
| Maven:io.netty:netty-handler | 4.2.15.Final | Package registry (OSV) |
| opensuse:netty | 4.1.135-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:eap8-eap-product-conf-parent | 0:801.7.1-1.GA_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-eap-product-conf-wildfly-ee-feature-pack | 0:801.7.1-1.GA_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-netty | 0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-netty-buffer | 0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-netty-codec | 0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-netty-codec-dns | 0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-netty-codec-http | 0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-netty-codec-socks | 0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-netty-common | 0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-netty-handler | 0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-netty-handler-proxy | 0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| red hat:eap8-netty-resolver | 0:4.1.135-1.Final_redhat_00001.1.el10eap · Red Hat:jboss_enterprise_application_platform:8.1::el10 | Package registry (OSV) |
| suse:netty | 4.1.135-150200.4.50.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP7 | Package registry (OSV) |
| suse:netty-tcnative | 2.0.79-150200.3.45.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7 | Package 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.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-3387177 days apartNetty HTTP/2 CONTINUATION Frame Flood DoS via Zero-Byte Frame Bypass34Monitor
- CVE-2026-100660106 days apartNetty before 4.2.18.Final QpackEncoder Unbounded Memory Retention34Monitor
- CVE-2025-55163303 days apartNetty MadeYouReset HTTP/2 DDoS Vulnerability32Monitor
- CVE-2026-463400 days apartNetty: SCTP reassembly nests buffers without bound30Monitor
- CVE-2026-487480 days apartNetty HTTP/3 QPACK Blocked Streams Memory Exhaustion30Monitor
- CVE-2026-4258230 days apartNetty: HTTP/3 QPACK literal unbounded allocation30Monitor
Not on record for this CVE: patch commit or PR link · researcher credit · public bounty program.
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-770 · Allocation of Resources Without Limits or ThrottlingCVSS 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.
Attack patterns (CAPEC)
- FloodingCAPEC-125likelihood: High · Medium
- Excessive AllocationCAPEC-130likelihood: Medium · Medium
- XML Ping of the DeathCAPEC-147likelihood: Low · Medium
- Exponential Data ExpansionCAPEC-197likelihood: High · Medium
- Serialized Data Parameter BlowupCAPEC-229likelihood: High · High
- Serialized Data with Nested PayloadsCAPEC-230likelihood: Medium · High
- Oversized Serialized Data PayloadsCAPEC-231likelihood: Medium · High
- HTTP DoSCAPEC-469Low
ATT&CK techniques
- Network Denial of Service:Direct Network FloodT1498.001
- Network Denial of Service:Reflection AmplificationT1498.002
- Endpoint Denial of ServiceT1499
- Endpoint Denial of Service: OS Exhaustion FloodT1499.001
- Endpoint Denial of Service:Service Exhaustion FloodT1499.002
- Endpoint Denial of Service:Application Exhaustion FloodT1499.003
Change log (1)
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- github.com/netty/netty/releases/tag/netty-4.2.15.Final
- github.com/netty/netty/security/advisories/GHSA-x4gw-5cx5-pgmh
- access.redhat.com/errata/RHSA-2026:26017
- access.redhat.com/errata/RHSA-2026:26018
- access.redhat.com/errata/RHSA-2026:26586
- access.redhat.com/errata/RHSA-2026:28573
- access.redhat.com/errata/RHSA-2026:34608
- access.redhat.com/errata/RHSA-2026:37390
- access.redhat.com/errata/RHSA-2026:41951
- access.redhat.com/errata/RHSA-2026:48151
- access.redhat.com/errata/RHSA-2026:49700
- access.redhat.com/errata/RHSA-2026:49701
- access.redhat.com/errata/RHSA-2026:50085
- access.redhat.com/errata/RHSA-2026:53644
- access.redhat.com/errata/RHSA-2026:53645
- access.redhat.com/errata/RHSA-2026:53646
- access.redhat.com/errata/RHSA-2026:54435
- access.redhat.com/errata/RHSA-2026:62260
- access.redhat.com/errata/RHSA-2026:65126
Vendor advisories and official records. Exploit/PoC links are deliberately left out.