CVE-2026-84691: Software Security Vulnerability Vulnerability

HIGH
Advisory Identifier: GHSA-xrjh-rfcr-rxj7
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CVSS 8.7
CWE-134
Published
Advisory Summary

CVE-2026-84691 is a HIGH (CVSS 8.7) security vulnerability vulnerability (CWE-134: Use of Externally-Controlled Format String) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product uses a function that accepts a format string as an argument, but the format string originates from an external source.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-84691 at a Glance

CVE Identifier CVE-2026-84691
GHSA Identifier GHSA-xrjh-rfcr-rxj7
Severity HIGH
CVSS v3.1 Base Score 8.7
CWE Classification CWE-134: Use of Externally-Controlled Format String
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 8.7

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

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

How to Fix CVE-2026-84691

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-2026-84691, 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-134: Use of Externally-Controlled Format String, where the product uses a function that accepts a format string as an argument, but the format string originates from an external source. 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

A flaw was found in Red Hat Ansible Automation Platform's automation- controller. The setting that formats the log message emitted for API 4XX errors is an administrator-controlled Python format-string template that is rendered with a live user object as an argument. Because Python string formatting permits attribute and item traversal on its arguments, an administrator can craft a template that walks from the user object into the application settings and reads the Django secret key and the database password. The formatted message is written to a logger that can be forwarded to an external log aggregator, whose destination is also administrator-controlled, allowing the secrets to be sent off the host. An authenticated administrator can thereby obtain the master encryption key used to protect all stored credentials and the database service password, enabling offline decryption of every stored credential, forgery of user sessions, and direct access to the controller database.

References

NVD — CVE-2026-84691 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-84691
access.redhat.com/errata/rhsa-2026:71... WEB
https://access.redhat.com/errata/RHSA-2026:71113
access.redhat.com/errata/rhsa-2026:71... WEB
https://access.redhat.com/errata/RHSA-2026:71114
access.redhat.com/errata/rhsa-2026:71... WEB
https://access.redhat.com/errata/RHSA-2026:71177
access.redhat.com/errata/rhsa-2026:71... WEB
https://access.redhat.com/errata/RHSA-2026:71179
Software Security Information SECURITY
https://access.redhat.com/security/cve/CVE-2026-84691
bugzilla.redhat.com/show_bug.cgi WEB
https://bugzilla.redhat.com/show_bug.cgi?id=2527151

Frequently Asked Questions

What is CVE-2026-84691?
CVE-2026-84691 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-134: Use of Externally-Controlled Format String.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-84691?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-84691?
CVE-2026-84691 has a CVSS v3.1 base score of 8.7 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N.
What CWE is associated with CVE-2026-84691?
CVE-2026-84691 is classified under CWE-134: Use of Externally-Controlled Format String (The product uses a function that accepts a format string as an argument, but the format string originates from an external source.).
How can I check Maven dependencies for CVE-2026-84691?
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-xrjh-rfcr-rxj7",
  "modified" : "2026-09-24T06:31:13Z",
  "published" : "2026-09-23T21:30:57Z",
  "aliases" : [ "CVE-2026-84691" ],
  "details" : "A flaw was found in Red Hat Ansible Automation Platform's automation-\ncontroller. The setting that formats the log message emitted for API 4XX errors\nis an administrator-controlled Python format-string template that is rendered\nwith a live user object as an argument. Because Python string formatting permits\nattribute and item traversal on its arguments, an administrator can craft a\ntemplate that walks from the user object into the application settings and reads\nthe Django secret key and the database password. The formatted message is written\nto a logger that can be forwarded to an external log aggregator, whose destination\nis also administrator-controlled, allowing the secrets to be sent off the host. An\nauthenticated administrator can thereby obtain the master encryption key used to\nprotect all stored credentials and the database service password, enabling offline\ndecryption of every stored credential, forgery of user sessions, and direct\naccess to the controller database.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-84691"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2026:71113"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2026:71114"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2026:71177"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/errata/RHSA-2026:71179"
  }, {
    "type" : "WEB",
    "url" : "https://access.redhat.com/security/cve/CVE-2026-84691"
  }, {
    "type" : "WEB",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2527151"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-134" ],
    "severity" : "HIGH",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-23T20:17:17Z"
  }
}