CVE-2026-89044
Netty 4.1.133.Final through 4.1.137.Final and 4.2.13.Final through 4.2.17.Final HTTP Request Smuggling via Transfer-Encoding
Description
Netty versions 4.1.133.Final through 4.1.137.Final and 4.2.13.Final through 4.2.17.Final fail to properly validate the final transfer coding in the Transfer-Encoding header, allowing attackers to smuggle requests by using malformed encoding declarations. Attackers can split Transfer-Encoding headers across multiple lines or use values like 'chunked, xchunked' to bypass validation and decode messages as chunked when the final coding is not chunked, enabling request smuggling attacks.
INFO
Published Date :
Sept. 10, 2026, 6:18 p.m.
Last Modified :
Sept. 18, 2026, 6:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Netty to a patched version.
- Apply vendor security updates immediately.
- Validate HTTP header parsing logic.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-89044.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-89044 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-89044
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-89044 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-89044 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 18, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-89044', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-18T17:11:17.626681Z'} -
Initial Analysis by [email protected]
Sep. 16, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:* versions from (including) 4.1.133 up to (excluding) 4.1.138 *cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:* versions from (including) 4.2.13 up to (excluding) 4.2.18 Added Reference Type VulnCheck: https://github.com/netty/netty Types: Product Added Reference Type VulnCheck: https://github.com/netty/netty/blob/netty-4.1.137.Final/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java#L866 Types: Product Added Reference Type VulnCheck: https://github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500c Types: Patch Added Reference Type VulnCheck: https://github.com/netty/netty/commit/ca87393b0e9e13c493d213a268e727a6d44e1585 Types: Patch Added Reference Type VulnCheck: https://github.com/netty/netty/releases/tag/netty-4.1.138.Final Types: Release Notes Added Reference Type VulnCheck: https://github.com/netty/netty/releases/tag/netty-4.2.18.Final Types: Release Notes Added Reference Type VulnCheck: https://github.com/netty/netty/security/advisories/GHSA-hcvj-94mj-jp5c Types: Exploit, Vendor Advisory Added Reference Type VulnCheck: https://www.vulncheck.com/advisories/netty-4.1.133-final-through-4.1.137-final-and-4.2.13-final-through-4.2.17-final-http-request-smuggling-via-transfer-encoding Types: Patch, Third Party Advisory -
New CVE Received by [email protected]
Sep. 10, 2026
Action Type Old Value New Value Added Description Netty versions 4.1.133.Final through 4.1.137.Final and 4.2.13.Final through 4.2.17.Final fail to properly validate the final transfer coding in the Transfer-Encoding header, allowing attackers to smuggle requests by using malformed encoding declarations. Attackers can split Transfer-Encoding headers across multiple lines or use values like 'chunked, xchunked' to bypass validation and decode messages as chunked when the final coding is not chunked, enabling request smuggling attacks. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/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 Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N Added CWE CWE-444 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/89xxx/CVE-2026-89044.json">CVE-2026-89044</a> Added Reference https://github.com/netty/netty Added Reference https://github.com/netty/netty/blob/netty-4.1.137.Final/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java#L866 Added Reference https://github.com/netty/netty/commit/640d4d3324f7b811a4903d0730c8ccb35500500c Added Reference https://github.com/netty/netty/commit/ca87393b0e9e13c493d213a268e727a6d44e1585 Added Reference https://github.com/netty/netty/releases/tag/netty-4.1.138.Final Added Reference https://github.com/netty/netty/releases/tag/netty-4.2.18.Final Added Reference https://github.com/netty/netty/security/advisories/GHSA-hcvj-94mj-jp5c Added Reference https://www.vulncheck.com/advisories/netty-4.1.133-final-through-4.1.137-final-and-4.2.13-final-through-4.2.17-final-http-request-smuggling-via-transfer-encoding