CVE-2026-90452 CISA CVE debrief

Who should care

Defenders responsible for the configuration and security of reverse proxies and identity-provider services should assess their exposure to this vulnerability. Network administrators and security teams should also be aware of the potential risks and take steps to mitigate them.

Why it matters

CVE-2026-90452 is a medium-severity vulnerability that allows an attacker to impersonate an identity provider and issue forged authentication tokens. Defenders should verify configurations, assess network paths, and implement monitoring to mitigate potential risks.

• An attacker could issue forged authentication tokens, potentially leading to unauthorized access.
• The vulnerability requires verification of reverse proxy and identity-provider service configurations.
• Defenders need to assess their network paths to prevent exploitation.
• Remediation priority is medium due to the CVSS score of 6.

Technical summary

The vulnerability exists in the communication between a reverse proxy and an identity-provider service. The proxy does not verify the identity provider's server certificate, allowing an attacker to impersonate the identity provider. This impersonation can lead to the issuance of forged authentication tokens that are accepted by the deployment. Affected product deployments should be identified and verified for exposure. Defenders should prioritize verifying the configuration of reverse proxies and identity-provider services, ensuring proper certificate verification is in place.

Defensive priority

Defenders should prioritize verifying the configuration of reverse proxies and identity-provider services, ensuring proper certificate verification is in place.

Recommended defensive actions

• Verify the configuration of reverse proxies and identity-provider services to ensure proper certificate verification.
• Review network paths and segmentation to prevent attackers from positioning themselves between the proxy and identity provider.
• Implement monitoring to detect potential impersonation attempts and anomalous authentication token issuance.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description and CVSS score. However, additional information on affected versions, exploitation, and remediation is limited.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.