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NVD / CVE Program· CNA GitHub_M

CVE-2025-67735: Netty has a CRLF Injection vulnerability in io.netty.handler.codec.http.HttpRequestEncoder

Noroxi assessment

Priority: Monitor (action score 26/100)

  • 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: 0.32% (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.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: netty (Debian:11) 1:4.1.48-4+deb11u3; netty (Debian:12) 1:4.1.48-7+deb12u2; netty (Debian:13) 1:4.1.48-10+deb13u1.

Low priority for now. Upgrade to netty (Debian:11) 1:4.1.48-4+deb11u3; netty (Debian:12) 1:4.1.48-7+deb12u2; netty (Debian:13) 1:4.1.48-10+deb13u1 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. In versions prior to 4.1.129.Final and 4.2.8.Final, the `io.netty.handler.codec.http.HttpRequestEncoder` has a CRLF injection with the request URI when constructing a request. This leads to request smuggling when `HttpRequestEncoder` is used without proper sanitization of the URI. Any application / framework using `HttpRequestEncoder` can be subject to be abused to perform request smuggling using CRLF injection. Versions 4.1.129.Final and 4.2.8.Final fix the issue.

MediumCVSS 6.5 · v3.1—No exploit Fix available
Published
Dec 16, 2025
Updated
Oct 14, 2026
EPSS
0.3% · 24th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
6.5
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.

Follow CVE-2025-67735

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

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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.

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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 4.1.129
  • netty netty4.2.0 and later · before 4.2.8

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.Alpha1, < 4.2.8.Final, < 4.1.129.Finalaffected

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:11nettybefore 1:4.1.48-4+deb11u31:4.1.48-4+deb11u3
Debian:12nettybefore 1:4.1.48-7+deb12u21:4.1.48-7+deb12u2
Debian:13nettybefore 1:4.1.48-10+deb13u11:4.1.48-10+deb13u1
Debian:14nettybefore 1:4.1.48-161:4.1.48-16
Mavenio.netty:netty-codec-httpfrom 4.2.0.Alpha1 · before 4.2.8.Final4.2.8.Final
Mavenio.netty:netty-codec-httpbefore 4.1.129.Final4.1.129.Final
openSUSE:Leap 15.6nettybefore 4.1.130-150200.4.40.14.1.130-150200.4.40.1
openSUSE:Tumbleweednettybefore 4.1.130-1.14.1.130-1.1
SUSE:Linux Enterprise Module for Package Hub 15 SP7nettybefore 4.1.130-150200.4.40.14.1.130-150200.4.40.1

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-2025-58057Sep 4, 2025 · Netty's BrotliDecoder is vulnerable to DoS via zip bomb style attack
    27Monitor
  • ← EarlierCVE-2025-59419Oct 15, 2025 · Netty netty-codec-smtp SMTP Command Injection Vulnerability Allowing Email Forgery
    22Monitor
  • Later →CVE-2026-33870Mar 27, 2026 · Netty: HTTP Request Smuggling via Chunked Extension Quoted-String Parsing
    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
debian:netty1:4.1.48-7+deb12u2 · Debian:12Package registry (OSV)
Maven:io.netty:netty-codec-http4.1.129.FinalPackage registry (OSV)
Maven:io.netty:netty-codec-http4.2.8.FinalPackage registry (OSV)
opensuse:netty4.1.130-150200.4.40.1 · openSUSE:Leap 15.6Package registry (OSV)
suse:netty4.1.130-150200.4.40.1 · SUSE:Linux Enterprise Module for Package Hub 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.

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-2026-42586148 days apartNetty: CRLF Injection in Netty Redis Codec Encoder
    28Monitor
  • CVE-2026-59921224 days apartNetty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder
    26Monitor
  • CVE-2026-59920225 days apartNetty: STOMP CONNECT Frame Header Injection
    26Monitor
  • CVE-2025-5941962 days apartNetty netty-codec-smtp SMTP Command Injection Vulnerability Allowing Email Forgery
    22Monitor
  • CVE-2026-59919225 days apartNetty: HAProxy V1 Protocol CRLF Injection via AF_UNIX Address
    22Monitor
  • CVE-2026-41417141 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

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

Weakness class (CWE)

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

CVSS vector

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

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.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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