Skip to content
Noroxi
NVD / CVE Program· CNA GitHub_M

CVE-2026-42586: Netty: CRLF Injection in Netty Redis Codec Encoder

Noroxi assessment

Priority: Monitor (action score 28/100)

  • 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: 0.21% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: netty netty 4.2.13.Final.

Low priority for now. Upgrade to netty netty 4.2.13.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 is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, the Netty Redis codec encoder (RedisEncoder) writes user-controlled string content directly to the network output buffer without validating or sanitizing CRLF (\r\n) characters. Since the Redis Serialization Protocol (RESP) uses CRLF as the command/response delimiter, an attacker who can control the content of a Redis message can inject arbitrary Redis commands or forge fake responses. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.

HighCVSS 7.1 · v3.1—No exploit Fix available
Published
May 13, 2026
Updated
Oct 26, 2026
EPSS
0.2% · 12th percentile

Report tools

JSON

Action score

28

Monitor

Low priority for now.

CVSS
28 / 40 · 7.1 / 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
7.1
CNA · GitHub_M
6.8
0.3 point gap

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

Follow CVE-2026-42586

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for netty records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

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 help

Affected 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.

VendorProduct
nettynetty

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • netty nettybefore 4.1.133
  • netty netty4.2.0 and later · before 4.2.13

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.

  • io.netty netty-codec-redis

    • >= 4.2.0.Alpha1, < 4.2.13.Final, < 4.1.133.Finalaffected

  • netty netty

    • >= 4.2.0.Alpha1, < 4.2.13.Final, < 4.1.133.Finalaffected

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12nettyfrom 0—
Mavenio.netty:netty-codec-redisfrom 4.2.0.Alpha1 · before 4.2.13.Final4.2.13.Final
Mavenio.netty:netty-codec-redisbefore 4.1.133.Final4.1.133.Final
openSUSE:Tumbleweednettybefore 4.1.133-1.14.1.133-1.1
SUSE:Linux Enterprise Module for Development Tools 15 SP7netty-tcnativebefore 2.0.77-150200.3.39.12.0.77-150200.3.39.1
SUSE:Linux Enterprise Module for Package Hub 15 SP7nettybefore 4.1.133-150200.4.46.14.1.133-150200.4.46.1

Same product

netty: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-47691Netty has Insufficient Bailiwick Validation for NS Records
    40Plan
  • CVE-2026-45674Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records
    40Plan
  • 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 Tr
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-42584May 13, 2026 · Netty: HttpClientCodec response desynchronization
    36Monitor
  • ← EarlierCVE-2026-42585May 13, 2026 · Netty: HTTP Request Smuggling due to malformed Transfer-Encoding
    30Monitor
  • Later →CVE-2026-42587May 13, 2026 · Netty: HttpContentDecompressor maxAllocation bypass via Content-Encoding: br/zstd/snappy enables decompression bomb DoS
    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
netty netty4.2.13.Final · descriptionVendor (CNA)
Maven:io.netty:netty-codec-redis4.1.133.FinalPackage registry (OSV)
Maven:io.netty:netty-codec-redis4.2.13.FinalPackage registry (OSV)
opensuse:netty4.1.133-1.1 · openSUSE:TumbleweedPackage registry (OSV)
suse:netty4.1.133-150200.4.46.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP7Package registry (OSV)
suse:netty-tcnative2.0.77-150200.3.39.1 · SUSE:Linux Enterprise Module for Development Tools 15 SP7Package 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.

No history yet (it accumulates with the daily EPSS job).

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-2026-5992176 days apartNetty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder
    26Monitor
  • CVE-2026-5992077 days apartNetty: STOMP CONNECT Frame Header Injection
    26Monitor
  • CVE-2025-67735148 days apartNetty has a CRLF Injection vulnerability in io.netty.handler.codec.http.HttpRequestEncoder
    26Monitor
  • CVE-2026-5991977 days apartNetty: HAProxy V1 Protocol CRLF Injection via AF_UNIX Address
    22Monitor
  • CVE-2025-59419210 days apartNetty netty-codec-smtp SMTP Command Injection Vulnerability Allowing Email Forgery
    22Monitor
  • CVE-2026-414177 days apartNetty vulnerable to HTTP request smuggling and RTSP request injection via DefaultHttpRequest.setUri()
    21Monitor

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

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-93 · Improper Neutralization of CRLF Sequences ('CRLF Injection')

CVSS vector

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

nvd-primary

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

All records