CVE-2026-81036: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-g6qf-h8rr-h574
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CVSS 8.1
CWE-601
Published
Advisory Summary

CVE-2026-81036 is a HIGH (CVSS 8.1) security vulnerability vulnerability (CWE-601: URL Redirection to Untrusted Site ('Open Redirect')) affecting Software libraries in the Maven ecosystem. The weakness occurs when the web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-81036 at a Glance

CVE Identifier CVE-2026-81036
GHSA Identifier GHSA-g6qf-h8rr-h574
Severity HIGH
CVSS v3.1 Base Score 8.1
CWE Classification CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 8.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-81036

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-2026-81036, 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-601: URL Redirection to Untrusted Site ('Open Redirect'), where the web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect. 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

Stalwart Mail Server does not compare an OAuth redirect target against any registered destination in its default configuration. The validation routine in crates/http/src/auth/oauth/registration.rs returns success immediately when the client-authentication requirement is disabled, and that requirement is false in the shipped settings, so the supplied redirect value is neither matched against a registered client nor otherwise constrained. The value is stored with the authorization code, and the login page reads it back and sends the browser to it with the code attached. A request naming a destination the attacker controls therefore delivers a valid authorization code there once the account holder authenticates, and because the token endpoint checks only that the redirect presented at exchange matches the one recorded with the code, the same party can exchange it for access and refresh tokens and read the account's mail.

References

NVD — CVE-2026-81036 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-81036
Software Source Repository REPOSITORY
https://github.com/stalwartlabs/stalwart/issues/3205
Software Source Repository REPOSITORY
https://github.com/stalwartlabs/stalwart
Software Source Repository REPOSITORY
https://github.com/stalwartlabs/stalwart/blob/v0.16.19/crates/http/src/auth/oauth/registration.rs
www.vulncheck.com/advisories/stalwart... WEB
https://www.vulncheck.com/advisories/stalwart-mail-server-through-0.16.19-authorization-code-disclosure-via-unvalidated-oauth-redirect-uri

Frequently Asked Questions

What is CVE-2026-81036?
CVE-2026-81036 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-601: URL Redirection to Untrusted Site ('Open Redirect').
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-81036?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-81036?
CVE-2026-81036 has a CVSS v3.1 base score of 8.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-81036?
CVE-2026-81036 is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect') (The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.).
How can I check Maven dependencies for CVE-2026-81036?
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-g6qf-h8rr-h574",
  "modified" : "2026-08-26T18:31:56Z",
  "published" : "2026-08-26T18:31:56Z",
  "aliases" : [ "CVE-2026-81036" ],
  "details" : "Stalwart Mail Server does not compare an OAuth redirect target against any registered destination in its default configuration. The validation routine in crates/http/src/auth/oauth/registration.rs returns success immediately when the client-authentication requirement is disabled, and that requirement is false in the shipped settings, so the supplied redirect value is neither matched against a registered client nor otherwise constrained. The value is stored with the authorization code, and the login page reads it back and sends the browser to it with the code attached. A request naming a destination the attacker controls therefore delivers a valid authorization code there once the account holder authenticates, and because the token endpoint checks only that the redirect presented at exchange matches the one recorded with the code, the same party can exchange it for access and refresh tokens and read the account's mail.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/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"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-81036"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/stalwartlabs/stalwart/issues/3205"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/stalwartlabs/stalwart"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/stalwartlabs/stalwart/blob/v0.16.19/crates/http/src/auth/oauth/registration.rs"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/stalwart-mail-server-through-0.16.19-authorization-code-disclosure-via-unvalidated-oauth-redirect-uri"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-601" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-26T16:16:46Z"
  }
}