Netty before 4.2.16.Final SOCKS Proxy Null Byte Injection
Noroxi assessment
Priority: Monitor (action score 25/100)
- 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: 0.25% (FIRST EPSS).
- 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.
- Fixed version: netty netty 4.2.17.Final.
Low priority for now. Upgrade to netty netty 4.2.17.Final 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 (io.netty:netty-codec-socks) versions 4.2.0.Final through 4.2.16.Final and 4.1.x through 4.1.136.Final contain null byte, CRLF, and credential injection vulnerabilities in the SOCKS4 (Socks4ClientEncoder) and SOCKS5 (Socks5ClientEncoder) client encoders, which fail to validate domain address and authentication (username/password) fields. An attacker able to control these fields can inject null bytes or CRLF characters to truncate or alter values, potentially enabling domain spoofing, SOCKS4 userid truncation, authentication data injection, and protocol confusion. Fixed in 4.2.17.Final and 4.1.137.Final.
- Published
- Aug 22, 2026
- Updated
- Oct 14, 2026
- EPSS
- 0.2% · 15th percentile
- CWE
- CWE-626
Report tools
Action score
25
Monitor
Low priority for now.
- CVSS
- 25 / 40 · 6.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · VulnCheck
- 6.3
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
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.
Running WordPress? Scan your site free with WP Lens
Noroxi 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 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- netty nettybefore 4.1.137
- netty netty4.2.0 and later · before 4.2.17
Versions reported by the vendor
Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.
netty netty
- 4.2.16.Final, 4.1.137.Finalnot affected
- 4.2.0.Final and later · before 4.2.16.Finalaffected
- before 4.1.137.Finalaffected
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 | — |
| openSUSE:Tumbleweed | netty | before 4.1.138-1.1 | 4.1.138-1.1 |
| SUSE:Linux Enterprise Module for Development Tools 15 SP7 | netty-tcnative | before 2.0.84-150200.3.51.1 | 2.0.84-150200.3.51.1 |
| SUSE:Linux Enterprise Module for Package Hub 15 SP7 | netty | before 4.1.138-150200.4.56.1 | 4.1.138-150200.4.56.1 |
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 Tr40Plan
Published before and after this one in the same product
- ← EarlierCVE-2026-75596Aug 19, 2026 · Netty: Fragmented ClientHello records trigger quadratic pre-handshake reassembly in default SNI parsing34Monitor
- ← EarlierCVE-2026-62243Aug 22, 2026 · Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass34Monitor
- Later →CVE-2026-76816Aug 24, 2026 · Netty: MQTT Topic Name and Client ID Validation Bypass14Monitor
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 |
|---|---|---|
| netty netty | 4.2.17.Final · description | Vendor (CNA) |
| opensuse:netty | 4.1.138-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| suse:netty | 4.1.138-150200.4.56.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP7 | Package registry (OSV) |
| suse:netty-tcnative | 2.0.84-150200.3.51.1 · 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).
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 researchersFinders, 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.
No nightly-computed relations.
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
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-626 · Null Byte Interaction Error (Poison Null Byte)CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (1 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.