CVE-2026-107276
Deferred Deferred - Pending Action

Race Condition in MISP Email OTP Login Allows Concurrent Authentication

Publication date: 2026-10-07

Last updated on: 2026-10-07

Assigner: CIRCL

Description
MISP contains a race condition in the email-based one-time password (OTP) login flow. When two HTTP requests carrying the same valid OTP are submitted concurrently, both can successfully authenticate and establish a session. The root cause is that the OTP value is read from the shared store, validated, and then deleted in separate non-atomic steps, allowing a second in-flight request to read the same value before the first request's deletion takes effect. Preconditions: - The target MISP instance has email OTP login enabled. - The attacker possesses a valid, unexpired OTP (e.g., via email interception or social engineering). - The attacker can issue two HTTP POST requests in close temporal proximity. Impact: - The one-time-use guarantee of the OTP is violated; a single code can yield two authenticated sessions. - This weakens the authentication control and may facilitate unauthorized access if the OTP is shared or intercepted. Affected versions: <2.5.48

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-10-07
Last Modified
2026-10-07
Generated
2026-10-07
AI Q&A
2026-10-07
EPSS Evaluated
N/A
NVD
CVE-2026-107276
EUVD
EUVD-2026-94395

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
MISP MISP 0

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-362 The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.
CWE-367 The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

MISP has a race condition in its email-based one-time password (OTP) login system. When two requests with the same valid OTP are sent at the same time, both can log in successfully. This happens because the OTP is checked and deleted in separate steps, allowing a second request to use the OTP before it is deleted by the first request.

Detection Guidance

To detect this vulnerability, monitor authentication logs for duplicate successful logins using the same OTP within a short timeframe. Check for concurrent HTTP POST requests to the OTP login endpoint with identical OTP values. Review Redis logs for OTP deletion operations to verify if multiple sessions are created from a single OTP.

Impact Analysis

This vulnerability allows an attacker to use a single OTP to create two authenticated sessions, bypassing the one-time-use security control. If the OTP is intercepted or shared, unauthorized access to the MISP instance could occur, potentially leading to data breaches or account compromise.

Compliance Impact

This vulnerability weakens authentication controls, which may violate compliance requirements for strong access controls in standards like GDPR and HIPAA. It could lead to unauthorized data access, potentially resulting in non-compliance with data protection regulations.

Mitigation Strategies

Upgrade MISP to version 2.5.48 or later to apply the patch that ensures atomic OTP validation and deletion. If immediate upgrade is not possible, disable email-based OTP login temporarily until the fix is applied.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-107276. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart