CVE-2023-51663 is a medium-severity (CVSS 5.3) CWE-289 vulnerability in hail. A fix is available for hail — see the affected versions and patch details below.
Hail authentication can be bypassed by changing email address
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-51663.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
hailReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Impact
All Hail Batch clusters are affected. An attacker is able to:
- Create one or more accounts with Hail Batch without corresponding real accounts in the organization.
For example, a user could create a Microsoft or Google account and then change their email to "[email protected]". This Microsoft or Google account can then be used to create a Hail Batch account in Hail Batch clusters whose organization domain is "example.org".
In Google, this attack is partially mitigated because Google requires users to verify ownership of their Google account. However, a valid user is able to create multiple distinct Hail Batch accounts by creating multiple distinct Google accounts using email addresses of the form "[email protected]".
In Microsoft, this attack requires Azure AD Administrator access to an Azure AD Tenant. The Azure AD Administrator is permitted to change the email address of an account to any other email address without verification. An attacker can create an Azure Tenant for free.
- The attacker does not have access to any private data (because the new service principals or service accounts are not granted any privileges).
- If trial Hail Batch billing projects are enabled, the attacker does have the ability to run jobs and thus spend money. An attacker can create as many accounts as Microsoft or Google permit.
- The attacker cannot impersonate another user because, in Azure, we use the
subfrom the OAuth2 response, and, in Google, Google does an email verification.
Remediation
- Apply this patch to prevent third-party attackers from creating accounts.
- Audit your users list https://auth.example.org/users for user accounts whose login ids are not valid login ids with your identity provider. Delete such users.
A forthcoming change will prevent users from creating multiple accounts using Google's + email redirection.
Workarounds
None.
References
- https://trufflesecurity.com/blog/google-oauth-is-broken-sort-of/
- https://www.descope.com/blog/post/noauth
- https://developers.google.com/identity/openid-connect/openid-connect#an-id-tokens-payload
- https://learn.microsoft.com/en-us/entra/identity-platform/access-token-claims-reference#payload-claims
[1] Hail Batch must separately stop using emails and start using the OAuth2 sub in Google. This is a known deficiency. In particular, if an email is re-used by the organization for a new user, the new user could access the old user's Hail Batch account.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | hail | all versions | 0.2.127pip install --upgrade 'hail==0.2.127' |
Affected Products
hailhailDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hail, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update hail to 0.2.127 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-51663 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2023-51663 in your dependencies?
Find it across PyPI, including transitive dependencies.