Impact
The partial-pipeline resume mechanism accepted partial_token as a bearer credential without binding it to the browser session that created it.
Applications using resumable partial pipeline steps could allow an attacker to start an authentication flow, obtain a valid partial token and verification data, and cause a victim's browser to resume that attacker-controlled flow. This could authenticate the victim's browser as the attacker's account.
The issue affects applications using partial pipeline steps such as mail_validation or custom steps decorated with @partial.
Patches
The issue has been fixed by binding partial pipeline resumes to the originating browser session.
Users should upgrade to a patched version.
Fix:
Workarounds
Applications that cannot upgrade immediately should disable resumable partial pipeline steps, including mail_validation and custom steps decorated with @partial.
If those flows are required, applications should avoid accepting partial resume links from untrusted contexts until a patched version can be deployed.
There is no complete workaround while continuing to use the vulnerable partial-pipeline resume mechanism.
References
Reported through GitHub private vulnerability reporting by Liyi Zhou, Ziyue Wang, Strick, Maurice, and Chenchen Yu from the University of Sydney security research team.
Reporter references:
mauriceng98 Reporter
nijel Remediation developer
Impact
The partial-pipeline resume mechanism accepted
partial_tokenas a bearer credential without binding it to the browser session that created it.Applications using resumable partial pipeline steps could allow an attacker to start an authentication flow, obtain a valid partial token and verification data, and cause a victim's browser to resume that attacker-controlled flow. This could authenticate the victim's browser as the attacker's account.
The issue affects applications using partial pipeline steps such as
mail_validationor custom steps decorated with@partial.Patches
The issue has been fixed by binding partial pipeline resumes to the originating browser session.
Users should upgrade to a patched version.
Fix:
Workarounds
Applications that cannot upgrade immediately should disable resumable partial pipeline steps, including
mail_validationand custom steps decorated with@partial.If those flows are required, applications should avoid accepting partial resume links from untrusted contexts until a patched version can be deployed.
There is no complete workaround while continuing to use the vulnerable partial-pipeline resume mechanism.
References
Reported through GitHub private vulnerability reporting by Liyi Zhou, Ziyue Wang, Strick, Maurice, and Chenchen Yu from the University of Sydney security research team.
Reporter references: