CVE-2026-33586: Software Security Vulnerability Vulnerability

MODERATE
Advisory Identifier: GHSA-rpc3-43rh-hpm4
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CWE-290
Published
Advisory Summary

CVE-2026-33586 is a MODERATE security vulnerability vulnerability (CWE-290: Authentication Bypass by Spoofing) affecting Software libraries in the Maven ecosystem. The weakness occurs when this attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-33586 at a Glance

CVE Identifier CVE-2026-33586
GHSA Identifier GHSA-rpc3-43rh-hpm4
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-290: Authentication Bypass by Spoofing
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-33586

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-2026-33586, 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-290: Authentication Bypass by Spoofing, where this attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. 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

Authenticated users are able to manipulate both the SMTP envelope “Envelope-from” and “From” fields when sending emails through OVH mail servers. Due to OVH's default SPF configuration, which commonly includes include:mx.ovh.com, any authenticated user with a valid OVH email account can send messages that appear to originate from any OVH-hosted domains using the default SPF record. Since the SPF policy explicitly authorizes OVH mail servers (mx.ovh.com) to send mail on behalf of these domains, forged messages successfully pass SPF validation despite not being authorized by the impersonated domain owner.

References

NVD — CVE-2026-33586 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33586
docs.ovhcloud.com/en/guides/web-cloud... WEB
https://docs.ovhcloud.com/en/guides/web-cloud/email-and-collaborative-solutions/troubleshooting/email-rejected-cross-domain-spoofing

Frequently Asked Questions

What is CVE-2026-33586?
CVE-2026-33586 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-290: Authentication Bypass by Spoofing.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-33586?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-33586?
CVE-2026-33586 is classified under CWE-290: Authentication Bypass by Spoofing (This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.).
How can I check Maven dependencies for CVE-2026-33586?
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-rpc3-43rh-hpm4",
  "modified" : "2026-10-07T18:32:09Z",
  "published" : "2026-10-07T18:32:09Z",
  "aliases" : [ "CVE-2026-33586" ],
  "details" : "Authenticated users are able to manipulate both the SMTP\nenvelope “Envelope-from” and “From” fields when sending\nemails through OVH mail servers.\n\n\n\nDue to OVH's default SPF configuration, which\ncommonly includes include:mx.ovh.com, any authenticated user with a\nvalid OVH email account can send messages that appear to originate from any\nOVH-hosted domains using the default SPF record. Since the SPF policy\nexplicitly authorizes OVH mail servers (mx.ovh.com) to send mail on behalf of\nthese domains, forged messages successfully pass SPF validation despite\nnot being authorized by the impersonated domain owner.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/SA:N/E:A/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"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-33586"
  }, {
    "type" : "WEB",
    "url" : "https://docs.ovhcloud.com/en/guides/web-cloud/email-and-collaborative-solutions/troubleshooting/email-rejected-cross-domain-spoofing"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-290" ],
    "severity" : "MODERATE",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-10-07T16:17:47Z"
  }
}