CVE-2026-19553: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-xx9w-qm94-hghj
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CWE-297
Published
Advisory Summary

CVE-2026-19553 is a HIGH security vulnerability vulnerability (CWE-297: Improper Validation of Certificate with Host Mismatch) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product communicates with a host that provides a certificate, but the product does not properly ensure that the certificate is actually associated with that host.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-19553 at a Glance

CVE Identifier CVE-2026-19553
GHSA Identifier GHSA-xx9w-qm94-hghj
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-297: Improper Validation of Certificate with Host Mismatch
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-19553

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-19553, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-297: Improper Validation of Certificate with Host Mismatch, where the product communicates with a host that provides a certificate, but the product does not properly ensure that the certificate is actually associated with that host. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

ssl.SSLContext.wrap_bio() didn't require the server_hostname argument to not be None if ssl.SSLContext.check_hostname was set. Due to a missing parameter check in SSLObject, if the server_hostname argument isn't supplied then hostname verification would be silently skipped. This defect could lead to programs where certificate hostname verification *appeared* to be succeeding with SSLContext.check_hostname = True and no ValueError being raised due to misconfiguration. If the program passes a server_hostname value that isn't an empty string or None to any of these APIs then certificate hostname verification proceeds as expected and the program is not affected by this vulnerability. Mitigating this vulnerability doesn't require updating Python or applying the patch. To mitigate, pass a valid non-None and non-empty server_hostname value to SSLContext.wrap_bio(), asyncio.create_connection(), or asyncio.loop.start_tls() and certificate hostname verification will proceed as expected. Upgrading to the latest version of Python or applying the patch only changes the behavior from silently skipping hostname verification to raising a ValueError, similar to SSLContext.wrap_socket(), when server_hostname isn't supplied.

References

NVD — CVE-2026-19553 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-19553
Software Source Repository REPOSITORY
https://github.com/python/cpython/issues/156793
Software Source Repository REPOSITORY
https://github.com/python/cpython/pull/158503
Security Fix Commit FIX COMMIT
https://github.com/python/cpython/commit/1697ea386c707142555d98a1263176bbbc014a96
Security Fix Commit FIX COMMIT
https://github.com/python/cpython/commit/5867d4e4ae6d1062352baf6b497a4026e8578ccf
Security Fix Commit FIX COMMIT
https://github.com/python/cpython/commit/641390146a16a38e6701923f4ee4f1940ae77082
Security Fix Commit FIX COMMIT
https://github.com/python/cpython/commit/869069d52ce0efab2f8c38197e92cdaaa312f1ed
Security Fix Commit FIX COMMIT
https://github.com/python/cpython/commit/966bf426d0b6c31c1b0a255ff14a17143a466ced
Security Fix Commit FIX COMMIT
https://github.com/python/cpython/commit/bdebbf9b366ec91e9cd9daa0b3510c9e84b60b80
Security Fix Commit FIX COMMIT
https://github.com/python/cpython/commit/f4e43ba525187282f2011da0e6ffc0d2b08d8062
Software Security Information SECURITY
https://mail.python.org/archives/list/security-announce@python.org/thread/QNZRG3YOAMTHDCMVCICXGY6YEFPY2VDL
Software Security Information SECURITY
http://www.openwall.com/lists/oss-security/2026/09/30/16

Frequently Asked Questions

What is CVE-2026-19553?
CVE-2026-19553 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-297: Improper Validation of Certificate with Host Mismatch.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-19553?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-19553?
CVE-2026-19553 is classified under CWE-297: Improper Validation of Certificate with Host Mismatch (The product communicates with a host that provides a certificate, but the product does not properly ensure that the certificate is actually associated with that host.).
How can I check Maven dependencies for CVE-2026-19553?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xx9w-qm94-hghj",
  "modified" : "2026-10-01T03:31:11Z",
  "published" : "2026-09-30T18:33:49Z",
  "aliases" : [ "CVE-2026-19553" ],
  "details" : "ssl.SSLContext.wrap_bio() didn't require the server_hostname argument\nto not be None if ssl.SSLContext.check_hostname was set. Due to a\nmissing parameter check in SSLObject, if the server_hostname argument\nisn't supplied then hostname verification would be silently skipped.\n\n\nThis defect could lead to programs where certificate hostname verification\n*appeared* to be succeeding with SSLContext.check_hostname = True and no\nValueError being raised due to misconfiguration.\n\n\nIf the program passes a server_hostname value that isn't an empty string\nor None to any of these APIs then certificate hostname verification\nproceeds as expected and the program is not affected by this vulnerability.\n\n\nMitigating this vulnerability doesn't require updating Python or applying\nthe patch. To mitigate, pass a valid non-None and non-empty\nserver_hostname value to SSLContext.wrap_bio(),\nasyncio.create_connection(), or asyncio.loop.start_tls() and\ncertificate hostname verification will proceed as expected. Upgrading to\nthe latest version of Python or applying the patch only changes the\nbehavior from silently skipping hostname verification to raising a\nValueError, similar to SSLContext.wrap_socket(), when server_hostname\nisn't supplied.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/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"
  } ],
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    "type" : "WEB",
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  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-297" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-30T17:16:45Z"
  }
}