CVE-2026-57574: CWE-294: Authentication Bypass by Capture-replay in misskey-dev misskey
Misskey is an open source, federated social media platform. Prior to 2026.6.0, Misskey contains a vulnerability in Time-based One-Time Password (TOTP) authentication in UserAuthService where insufficient validation of used tokens allows the reuse of a single-use code within its valid time step. If both credentials and a TOTP code are obtained concurrently, an attacker may reuse the code to perform unauthorized actions, potentially leading to account takeover. This issue is fixed in version 2026.6.0.
AI Analysis
Technical Summary
CVE-2026-57574 describes an authentication bypass vulnerability in Misskey's UserAuthService TOTP implementation. The vulnerability arises because the system does not properly invalidate a TOTP code after use within its valid time window, allowing replay of the same code. If an attacker obtains valid user credentials and a TOTP code simultaneously, they can reuse the code to bypass authentication controls. This flaw affects all versions prior to 2026.6.0 and is addressed by a fix in that version.
Potential Impact
Successful exploitation allows an attacker to bypass TOTP-based two-factor authentication by replaying a single-use code, enabling unauthorized access to user accounts. This can lead to account takeover and unauthorized actions within the affected Misskey platform instances.
Mitigation Recommendations
Upgrade Misskey to version 2026.6.0 or later, where this vulnerability is fixed. Patch status is confirmed by the vendor stating the issue is resolved in 2026.6.0. No other mitigation is indicated.
CVE-2026-57574: CWE-294: Authentication Bypass by Capture-replay in misskey-dev misskey
Description
Misskey is an open source, federated social media platform. Prior to 2026.6.0, Misskey contains a vulnerability in Time-based One-Time Password (TOTP) authentication in UserAuthService where insufficient validation of used tokens allows the reuse of a single-use code within its valid time step. If both credentials and a TOTP code are obtained concurrently, an attacker may reuse the code to perform unauthorized actions, potentially leading to account takeover. This issue is fixed in version 2026.6.0.
CVSS v4.0
Score 7.4high
Affected software
pkg:github/misskey-dev/misskeyRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-57574 describes an authentication bypass vulnerability in Misskey's UserAuthService TOTP implementation. The vulnerability arises because the system does not properly invalidate a TOTP code after use within its valid time window, allowing replay of the same code. If an attacker obtains valid user credentials and a TOTP code simultaneously, they can reuse the code to bypass authentication controls. This flaw affects all versions prior to 2026.6.0 and is addressed by a fix in that version.
Potential Impact
Successful exploitation allows an attacker to bypass TOTP-based two-factor authentication by replaying a single-use code, enabling unauthorized access to user accounts. This can lead to account takeover and unauthorized actions within the affected Misskey platform instances.
Mitigation Recommendations
Upgrade Misskey to version 2026.6.0 or later, where this vulnerability is fixed. Patch status is confirmed by the vendor stating the issue is resolved in 2026.6.0. No other mitigation is indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-24T18:49:56.208Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a515e2368715ace43325a17
Added to database: 07/10/2026, 21:03:31 UTC
Last enriched: 07/18/2026, 15:24:49 UTC
Last updated: 08/23/2026, 10:59:34 UTC
Views: 94
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