CVE-2026-81888

@hono/oauth-providers: OAuth state check fails open on omitted state, enabling login CSRF and forced account linking

MEDIUM
5.4
CVSS Score
Published: August 31, 2026 at 08:27 PM UTC
Updated: September 9, 2026 at 09:27 PM UTC
1 product affected across 1 vendor@hono/oauth Providers

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

@hono/oauth-providers is Authentication middleware for Hono. Prior to version 0.8.6, the built-in social login providers accept an OAuth callback even when the `state` value is absent on both sides, so the anti-CSRF check passes for a callback that never came from a genuine login attempt. This defeats the `state`-based CSRF protection under default usage. Version 0.8.6 has a patch.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.8.6
Affected range stops below 0.8.6, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.4MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-352CWE-1275

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