CVE-2025-61928 — better-auth
Fix: better-auth/better-auth@5560850CVE-2025-61928 is a CWE-285 vulnerability in better-auth. EPSS puts its 30-day exploitation probability at 17.9% (97th percentile). A fix is available for better-auth — see the affected versions and patch details below.
Better Auth: Unauthenticated API key creation through api-key plugin
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- 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.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-61928.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
better-authnpmDescription
Summary
A critical authentication bypass was identified in the API key creation and update endpoints. An attacker could create or modify API keys for arbitrary users by supplying a victim’s user ID in the request body. Due to a flaw in how the authenticated user was derived, the endpoints could treat attacker-controlled input as an authenticated user object under certain conditions.
Details
The vulnerability originated from fallback logic used when determining the current user. When no session was present, the handler incorrectly allowed request-body data to populate the user context used for authorization decisions. Because server-side validation only executed when authentication was required, privileged fields were not properly protected. As a result, the API accepted unauthenticated requests that targeted other users.
This same pattern affected both the API key creation and update routes.
Impact
Unauthenticated attackers could generate or modify API keys belonging to any user. This granted full authenticated access as the targeted user and, depending on the user’s privileges, could lead to account compromise, access to sensitive data, or broader application takeover.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | better-auth | all versions | 1.3.26npm install better-auth@1.3.26 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for better-auth, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update better-auth to 1.3.26 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-61928 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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-61928 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-61928. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-61928 in your dependencies?
O3 Security finds CVE-2025-61928 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.