NeuVector EUVD-2026-81415

Exploitation requires that NeuVector be configured to use SAML SSO against a corporate IdP that is SHARED with at least one other relying-party application, and that the attacker already possesses a legitimate account on one of those other applications behind that same IdP. The limiting factors are significant: the target must run NeuVector's SAML authentication (not the local/LDAP/OIDC paths), the IdP must issue assertions the attacker can obtain and replay, and the attacker needs valid credentials somewhere in the same federation (PR:L / AT:P). It does NOT require any pre-existing NeuVector account, admin access, or user interaction by a victim. Deployments using a dedicated IdP relying-party or IdP-side per-application audience enforcement are not exposed.

This is a genuine, high-priority authentication flaw despite the absence of exploitation telemetry. The vendor CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H) describes a remote, low-complexity bypass gated only by an attack requirement (AT:P) and a low privilege (PR:L) - namely, that the attacker already holds a legitimate account on some other application behind the same corporate IdP. The root cause is concrete and reliably reproducible: NeuVector fails to validate the SAML assertion's Audience/AudienceRestriction, generating but never reading the NotInAudience warning, so an assertion minted for a wiki/ticketing/expenses app is accepted verbatim. There is no probabilistic 'maybe it triggers' element - if the misconfiguration path is present it works deterministically. Signals are limited: no EPSS score, no CISA KEV listing, and no public POC are present in the input, so there is no evidence of active or automated exploitation (no public exploit identified at time of analysis). SSVC framework values were not supplied. The one conflict worth flagging is the privilege model: the attacker holds NO privilege on NeuVector itself, so PR:L reflects credentials on a DIFFERENT app federated to the same IdP - verify this reading against the vendor advisory. Net: high real-world severity for organizations running NeuVector with SAML SSO on a shared enterprise IdP, but the shared-IdP prerequisite and lack of exploit tooling keep it from being an emergency mass-exploitation event.

An employee who legitimately holds an account on a corporate wiki or ticketing tool federated to the same IdP as NeuVector authenticates there and captures the SAML assertion the IdP issues. Because NeuVector never checks the assertion's Audience, that assertion is replayed to NeuVector's SAML SSO endpoint and is accepted, logging the outsider into the container-security console. No public exploit code is identified in the provided data; the technique relies on standard SAML assertion handling rather than a bespoke tool.