CVE-2026-18141: Cert Validation Flaw (CVSS 8.2)

Description

A flaw was found in aap-gateway, a component of Ansible Automation Platform's Event-Driven Ansible (EDA). An unauthenticated remote attacker can bypass mutual Transport Layer Security (mTLS) authentication for event streams. This is achieved by manipulating the event stream URL and forging the HTTP Subject header. The system also inadvertently discloses the expected certificate subject in error messages, which simplifies the attack. This vulnerability allows an attacker to inject arbitrary events into EDA, potentially triggering automated workflows.

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CVSS v3.1 Score

8.2

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

EPSS — Exploit Prediction

0.0031

Probability of exploitation

0.23%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-295 CWE-295

References

Other References

https://access.redhat.com/errata/RHSA-2026:50336 https://access.redhat.com/errata/RHSA-2026:50340 https://access.redhat.com/errata/RHSA-2026:50479 https://access.redhat.com/security/cve/CVE-2026-18141 https://bugzilla.redhat.com/show_bug.cgi?id=2508155

Frequently Asked Questions

What is CVE-2026-18141? +

A flaw was found in aap-gateway, a component of Ansible Automation Platform's Event-Driven Ansible (EDA). An unauthenticated remote attacker can bypass mutual Transport Layer Security (mTLS) authentication for event streams. This is achieved by manipulating the event stream URL and forging the HTTP Subject header. The system also inadvertently discloses the expected certificate subject in error messages, which simplifies the attack. This vulnerability allows an attacker to inject arbitrary events into EDA, potentially triggering automated workflows. It has a CVSS v3.1 base score of 8.2 (HIGH).

How severe is CVE-2026-18141? +

CVE-2026-18141 has a CVSS v3.1 score of 8.2 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0031, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-18141? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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