Evidence-led vulnerability intelligence · 2026-08-06 13:46 IST

CVE-2025-15039

The Conditional Authentication (Adaptive Authentication) script does not correctly enforce the completion of all required authentication steps when a specific multi-step pattern involving certain authenticators is configured. This allows an attacker to bypass intermediate authentication challenges by exploiting how the script handles callbacks and re-execution of authentication steps. Successful exploitation allows a malicious actor to gain unauthorized access to a targeted user account. This vulnerability can only be exploited when all of the following conditions are met: the application login flow contains a specific secondary authenticator, the Conditional Authentication script is configured with particular event callbacks and re-executes an authentication step, the targeted user has one of the impacted authenticators enrolled, and the attacker successfully completes any preceding authentication steps.

CRITICAL · 9.4Azure / M365

Executive briefing

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Assessment: Potential exposure only — validate product, version, configuration and vendor applicability.

Evidence confidence: Not assessed Evidence-derived, not an exploitability verdict

Severity & attack characteristics

9.4 / 10 · CVSS

CVSS vector:
Not supplied

No CVSS vector is currently available in the source record.

Technical explanation & impact

Technical root-cause details are not available in the current source record.

Assess the impact using the published CVSS metrics and the affected vendor component.

Affected products and versions

NVD has not supplied machine-readable vulnerable CPE product/version entries for this CVE. This is an information gap, not proof that no products are affected. Check the vendor advisory references below.

Remediation & validation

  1. Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
  2. Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
  3. Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
  4. Validate the remediation with a version check and vulnerability rescan, then retain change evidence.

No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.

Vendor advisories, patches & exploit references

No external references are currently supplied in the CVE record.

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