MISP Email OTP Race Condition Allows One-Time Password to Be Consumed by Multiple Concurrent Requests

published 2026-10-07 33 d ago modified 2026-10-07 32 d ago also EUVD-2026-94395

cvss: 6.3; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits: 0; none known

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

Patch / fix

fixed in 1 links 1

MISP MISP 2.5.48

github.com/MISP/MISP@ba95e67 commit

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 32 d ago (2026-10-07)

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	6.3	CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
CNA	4.0	6.3	CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/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

Affected products

MISP MISP

Classification

Weakness

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition

References

github.com /MISP/MISP/commit/ba95e67d5
patch

Sources

CVE List CVE-2026-107276
NVD CVE-2026-107276

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary