CVE Intelligence
Critical Access control

CVE-2025-61928 — Better Auth: Unauthenticated API key creation through api-key plugin

Better Auth is an authentication and authorization library for TypeScript. In versions prior to 1.3.26, unauthenticated attackers can create or modify API keys for any user by passing that user's id in the request body to the `api/auth/api-key/create` route. `session?.user ?? (authRequired ? null : { id: ctx.body.userId })`. When no session exists but `userId` is present in the request body, `authRequired` becomes false and the user object is set to the attacker-controlled ID. Server-only field validation only executes when `authRequired` is true (lines 280-295), allowing attackers to set privileged fields. No additional authentication occurs before the database operation, so the malicious payload is accepted. The same pattern exists in the update endpoint. This is a critical authentication bypass enabling full an unauthenticated attacker can generate an API key for any user and immediately gain complete authenticated access. This allows the attacker to perform any action as the victim user using the api key, potentially compromise the user data and the application depending on the victim's privileges. Version 1.3.26 contains a patch for the issue.

Published Oct 9, 2025 · Updated Oct 19, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 18.8% (30-day exploitation probability)+15
  • Technical severity (critical)+10
  • CISA SSVC: exploitation "poc"+5
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
18.84%
ahead of 97% of scored CVEs · Oct 27, 2026
Affects
Better-auth
Better-auth
CVSS base
9.3
Critical · 3 source(s)
Prioritization reference: 8.6 provisional

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Npm Better-auth: fixed in version 1.3.26 — github.com (GitHub Security Advisories)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Better-auth Better-auth, Npm Better-auth).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. Apply the fixed version or the patch documented under Remediation.
  4. EPSS ahead of 97% of scored CVEs: prioritize it in the patch queue.
  5. Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Better-auth Better-auth version < 1.3.26 Vulnerable CVE Program (cve.org) e CISA ADP
Npm Better-auth < 1.3.26 Vulnerable GitHub Security Advisories

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Attack requirements
None
Privileges required
None
User interaction
None
Scope
X
Confidentiality (vulnerable system)
High
Integrity (vulnerable system)
High
Availability (vulnerable system)
High
Confidentiality (subsequent)
None
Integrity (subsequent)
None
Availability (subsequent)
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
9.3 CVSS 4.0 Critical — — security-advisories@github.com via NIST National Vulnerability Database
9.3 CVSS 4.0 Critical — — GitHub_M via CVE Program (cve.org) e CISA ADP
8.6 CVSS 3.1 High — — GitHub, Inc. via GitHub Security Advisories
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-285 · Improper Authorization

Other CVEs with this weakness →

EPSS over time FIRST

Oct 19, 2026 → Oct 27, 2026 · 9 reading(s) · max 18.84%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Audit administrative actions and access to resources outside each user’s normal pattern.
web/proxy/WAF logsnetwork IDS/IPSauthentication logsapplication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 19, 2026 · GitHub Security Advisories
  • Affected products added · npm/better-auth
    Oct 19, 2026 · GitHub Security Advisories
  • Affected products added · better-auth/better-auth
    Oct 19, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 19, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 19, 2026
  • CVSS changed · 9.3
    Oct 19, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 19, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 19, 2026 · NIST National Vulnerability Database
  • 2025
  • CVE published
    Oct 9, 2025 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 19, 2026 – Oct 19, 2026
  • 1× Official description updated · Oct 19, 2026 – Oct 19, 2026

References

4 on the record

Elsewhere on this site

Better-auth
every CVE for this vendor
Access control
same class
CWE-285
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-114607 better-auth: OAuth state can be used as a Magic Link to sign in as another user 5d
  • CVE-2026-110864 Better Auth 1.5.0-beta.12 before 1.7.7 Authentication Bypass via OAuth Proxy 13d
  • CVE-2026-110861 Better Auth drizzle-adapter 1.6.17 before 1.7.7 Rate Limit Bypass via Race Condition 13d
  • CVE-2026-110862 Better Auth 1.4.0-beta.18 before 1.7.7 Authentication Bypass via Magic Link 13d
  • CVE-2026-109346 better-auth 1.3.8-beta.3 before 1.7.0-rc.3 Device Authorization Phishing via /device 15d
  • CVE-2025-71401 better-auth before 1.4.2 basePath Modification DoS Aug 2, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-61928 is "Better Auth: Unauthenticated API key creation through api-key plugin", rated Critical. It affects Better-auth (Better-auth); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.3 describes technical severity. EPSS 18.84% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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