Who is accountable for fixing open redirect risk across application teams and authentication owners?

Application owners are accountable for the implementation, while security engineering is accountable for standards, testing, and review coverage. In practice, the teams building login, logout, SSO, OAuth, and email verification flows must enforce redirect validation and safe defaults. Security and engineering should share ownership of continuous testing so redirect bugs are caught before production.

Why This Matters for Security Teams

open redirect risk is often treated as a low-severity web issue, but it becomes a trust boundary problem when it sits inside login, logout, password reset, SSO, OAuth, or email verification flows. Those paths are where users decide whether a destination is legitimate, and attackers know how to turn an innocent redirect parameter into phishing, token theft, or session abuse. Under NIST Cybersecurity Framework 2.0, the accountability question maps to governance, control ownership, and repeated verification rather than one-time code review.

Security teams often miss this risk because the vulnerable code is spread across application teams, identity owners, and platform engineers, each assuming another group owns the final validation step. That gap is especially dangerous when redirect handling is reused through shared authentication libraries or default framework behaviour. The issue is not only whether a URL is allowed, but whether the design prevents user-controlled navigation from crossing trust boundaries in the first place. In practice, many security teams encounter open redirect abuse only after phishing, session misuse, or helpdesk escalation has already occurred, rather than through intentional control testing.

How It Works in Practice

Accountability should be split between the team that implements the flow and the team that defines and verifies the control standard. Application owners are responsible for fixing the code path, removing unsafe redirect logic, and ensuring the default behaviour is fail-closed. Authentication owners are responsible for the shared components, central sign-in patterns, SSO configuration, and identity journey rules that multiple applications inherit. Security engineering should define the validation standard, review high-risk flows, and test for bypasses across environments.

At a practical level, this means redirect targets should be allowlisted, normalized, and compared after parsing rather than by string matching alone. Relative paths are usually safer than arbitrary external URLs, but even those need validation if they can be chained into attacker-controlled destinations. Teams should also review:

• Login and logout return URLs
• Password reset and account recovery links
• OAuth and OIDC redirect URI handling
• Email verification and magic link destinations
• Error pages that preserve a next or continue parameter

Security testing should include direct and encoded payloads, nested redirects, schema changes, and open redirect chaining into credential harvesting or consent phishing. The control expectation is similar to the intent behind NIST SP 800-53 Rev 5 Security and Privacy Controls, where control ownership, secure configuration, and continuous assessment are part of normal assurance. Where application teams rely on framework defaults, the default must be reviewed, because “secure by default” is not universal across libraries or identity stacks. These controls tend to break down when redirect logic is duplicated across microservices and one legacy path still accepts unvalidated absolute URLs.

Common Variations and Edge Cases

Tighter redirect controls often increase delivery overhead, requiring organisations to balance user experience against abuse resistance. That tradeoff becomes visible when product teams want flexible post-login navigation while security teams want deterministic allowlists. Current guidance suggests that allowlisting named destinations is the safest pattern, but best practice is evolving for dynamic SaaS environments where tenant-specific paths, regional domains, or federated identity routes change frequently.

There is no universal standard for every edge case. For example, some environments legitimately need cross-domain redirects after authentication, especially in partner portals or multi-brand ecosystems. In those cases, the risk should be reduced with explicit registration, strong input normalization, signed state parameters, and monitoring for abnormal redirect patterns. ISO guidance on documented ownership and process control, such as ISO/IEC 27001:2022 Information Security Management, is useful here because the issue is not just code quality, but evidence that the organisation knows who approves, tests, and retests the control. A common mistake is assuming the authentication owner is solely responsible once the redirect is part of a shared SSO path; in practice, the app team still owns the last mile of validation.

Related resources from NHI Mgmt Group

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