Missing Rate Limiting in Email OTP Verification Allows Brute-Force Authentication Bypass
A vulnerability in MISP's email-based one-time password (OTP) authentication flow allowed an attacker to perform an unrestricted number of OTP verification attempts. The email_otp() endpoint did not apply brute-force protection when validating submitted OTP values. An attacker who had reached the OTP verification stage, for example after successfully providing a user's primary authentication credentials, could repeatedly submit candidate OTP values while the same OTP remained valid. This significantly increased the feasibility of guessing the OTP and bypassing the additional authentication factor, potentially resulting in unauthorized access to the affected user's account. The issue was exacerbated by the fact that the OTP is associated with the user rather than with an individual pending login session, allowing multiple concurrent sessions to attempt guesses against the same valid OTP. The patch integrates the existing MISP brute-force protection mechanism into the email OTP flow. Failed OTP attempts are now counted against the user, further attempts are rejected once the configured threshold is reached, and the active OTP is invalidated when the attempt budget is exhausted. Blocklisted users are also prevented from requesting the generation of a fresh OTP. In addition, OTP comparison now uses hash_equals() and validates that the submitted value is a string.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for help- Published
- Sep 3, 2026
- Updated
- Sep 11, 2026
- EPSS
- 0.5% · 37th percentile
- CWE
- CWE-307
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
34
Monitor
Low priority for now.
- CVSS
- 34 / 40 · 8.6 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · CIRCL
- 8.6
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:L/SI:N/SA:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| misp-project | misp | cpe:2.3:a:misp-project:misp |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- misp-project mispup to 2.5.45 inclusive
Versions reported by the vendor
Affected version ranges reported by the assigning authority (CIRCL). Independent of NVD's CPE analysis and usually ahead of it.
misp misp
- up to and including 2.5.45affected · semver
Same product
misp-project: all recordsOther highest-scoring records for the same primary product.
- CVE-2022-29528An issue was discovered in MISP before 2.4.158.40Plan
- CVE-2021-41326In MISP before 2.4.148, app/Lib/Export/OpendataExport.php mishandles parameter data that is used in a shell_exec call.40Plan
- CVE-2018-19908An issue was discovered in MISP 2.4.9x before 2.4.99.40Plan
- CVE-2015-5721Malware Information Sharing Platform (MISP) before 2.3.90 allows remote attackers to conduct PHP object injection attacks via crafted serial40Plan
- CVE-2015-5719app/Controller/TemplatesController.php in Malware Information Sharing Platform (MISP) before 2.3.92 does not properly restrict filenames und40Plan
- CVE-2024-29859In MISP before 2.4.187, add_misp_export in app/Controller/EventsController.php does not properly check for a valid file upload.39Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- Peter Jamesfinder
- Andras Iklodyremediation developer
- Scottish Government — National Cyber Teamfinder
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
—
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
- CVE-2026-5644773 days apartMISP remote code execution via arbitrary rdkafka configuration path37Monitor
- CVE-2026-5644673 days apartAuthenticated Remote Code Execution via Arbitrary NDJSON Error Log Path in MISP34Monitor
- CVE-2026-863474 days apartMISP Missing Authorization on Template File Upload Allows Authenticated Disk Exhaustion28Monitor
- CVE-2026-864194 days apartMISP Insufficient Outbound URL Validation Allows SSRF and Credential Disclosure via Feed Redirects and TAXII Discovery28Monitor
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-307 · Improper Restriction of Excessive Authentication AttemptsCVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:L/SI:N/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
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Dictionary-based Password AttackCAPEC-16likelihood: Medium · High
- Password Brute ForcingCAPEC-49likelihood: Medium · High
- Use of Known Domain CredentialsCAPEC-560likelihood: High · High
- Password SprayingCAPEC-565likelihood: High · High
- Credential StuffingCAPEC-600likelihood: High · High
- Use of Known Kerberos CredentialsCAPEC-652likelihood: Medium · High
- Use of Known Operating System CredentialsCAPEC-653likelihood: High · High
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.