MISP HOTP Token Replay via Stale Session-Cached Counter Allows Second-Factor Authentication Bypass
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-287.
Summary
MISP contains a vulnerability in its one-time password (OTP) authentication flow that allows replay of a consumed HOTP (paper) token and rewinding of the token counter. The HOTP verification logic compared the submitted token against a counter value that was cached in the user's session at the time the password was entered, rather than against the authoritative counter stored in the database. Because the session-cached counter is not updated after a token is successfully consumed, an attacker who holds a valid session (password already submitted) can reuse a previously burned HOTP token. The stale cached counter still matches the replayed token, granting a second successful authentication and effectively rewinding the counter state. Preconditions: - The target user has HOTP (paper token) second-factor authentication enabled. - The attacker possesses a valid session in which the password step has already been completed (the OTP step is pending). - The attacker has access to at least one HOTP token value (e.g., a paper token list). Security impact: - Bypass of the second authentication factor, allowing unauthorized access to a user's MISP account. - Corruption of the HOTP counter state, potentially invalidating subsequent legitimate tokens or enabling further replays. Affected versions: <2.5.48.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA MISP (MISP) Fixed in 2.5.48
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
MISP 2.5.48
6 records Highest priority Priority MEDIUM 1 MEDIUM, 5 LOW
Other records, highest priority first
- TI-2026-65744 MISP TOTP Code Replay Allows Duplicate Authentication Within Validity PeriodPriority MEDIUM 48
- TI-2026-65745 MISP: Object Distribution ACL Bypass via Event Flattening Exposes Organisation-Only AttributesPriority LOW 31
- TI-2026-65763 MISP Incomplete Thread Authorization Allows Unauthorized Read and Post Access to DiscussionsPriority LOW 23
Timeline
- 2026-10-02 Threatist record created from CVE-2026-103651
- 2026-10-03 Alias added: GHSA-28mq-63wc-4252
References
Patch 1
More MISP vulnerabilities
- TI-2025-41517 In MISP before 2.5.28, app/View/Elements/Workflows/executionPath.ctp allows XSS in the workflow execution path. CVSS 3.1CRITICAL 9.0
- TI-2026-65744 MISP TOTP Code Replay Allows Duplicate Authentication Within Validity Period CVSS 4.0CRITICAL 9.3
- TI-2026-54145 Path Traversal in MISP Object Template Resolution During STIX Import and Export in misp-stix library CVSS 4.0HIGH 8.8
- TI-2020-10250 MISP MISP-maltego 1.4.4 incorrectly shares a MISP connection across users in a remote-transform use case. CVSS 3.1CRITICAL 9.8
- TI-2026-59159 MISP Unauthenticated Mail Endpoints Allow Unbounded Storage Consumption and Request Flooding CVSS 4.0HIGH 8.7
- TI-2026-58541 MISP LDAP and LinOTP Authentication Bypass via Empty or Invalid Credentials CVSS 4.0CRITICAL 9.5
Sources
- CVE-2026-103651 · CVE Program
- CVE-2026-103651 · NVD
- FIRST EPSS
- GHSA-28mq-63wc-4252 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences