CVE-2026-62243
Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass
Description
Netty (io.netty:netty-handler) versions from 4.2.0.Final through 4.2.16.Final and versions through 4.1.136.Final disable TLS hostname verification on the SslProvider.OPENSSL client path when a plain (non-extended) X509TrustManager is used and Unsafe-based trust-manager wrapping is unavailable (Java 25+). In this configuration the OpenSSL client does not perform hostname verification, allowing a man-in-the-middle attacker to present a certificate issued for a different hostname that is accepted without validation. Fixed in 4.2.17.Final and 4.1.137.Final.
INFO
Published Date :
Aug. 22, 2026, 1:16 p.m.
Last Modified :
Aug. 22, 2026, 1:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-62243
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Netty to version 4.2.17.Final or later.
- Update Netty to version 4.1.137.Final or later.
- Ensure TLS hostname verification is enabled.
- Use a compatible X509TrustManager implementation.
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-2026-62243.
| URL | Resource |
|---|---|
| https://github.com/netty/netty/security/advisories/GHSA-p85m-gvr3-788c | |
| https://www.vulncheck.com/advisories/netty-through-tls-hostname-verification-bypass |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-62243 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-2026-62243
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-2026-62243 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-62243 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.
-
New CVE Received by [email protected]
Aug. 22, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'netty', 'product': 'netty', 'versions': [{'status': 'affected', 'version': '4.2.0.Final', 'lessThan': '4.2.16.Final', 'versionType': 'custom'}, {'status': 'unaffected', 'version': '4.2.16.Final', 'versionType': 'custom'}], 'packageURL': 'pkg:maven/io.netty/netty-handler', 'defaultStatus': 'unaffected'}, {'vendor': 'netty', 'product': 'netty', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '4.1.137.Final', 'versionType': 'custom'}, {'status': 'unaffected', 'version': '4.1.137.Final', 'versionType': 'custom'}], 'packageURL': 'pkg:maven/io.netty/netty-handler', 'defaultStatus': 'unaffected'}] Added Description Netty (io.netty:netty-handler) versions from 4.2.0.Final through 4.2.16.Final and versions through 4.1.136.Final disable TLS hostname verification on the SslProvider.OPENSSL client path when a plain (non-extended) X509TrustManager is used and Unsafe-based trust-manager wrapping is unavailable (Java 25+). In this configuration the OpenSSL client does not perform hostname verification, allowing a man-in-the-middle attacker to present a certificate issued for a different hostname that is accepted without validation. Fixed in 4.2.17.Final and 4.1.137.Final. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/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:H/I:N/A:N Added CWE CWE-297 Added Reference https://github.com/netty/netty/security/advisories/GHSA-p85m-gvr3-788c Added Reference https://www.vulncheck.com/advisories/netty-through-tls-hostname-verification-bypass