CVE-2026-2345 json
Insufficient Origin Validation in Proctorio Chrome Extension postMessage Handlers
published 8mo ago modified 4mo ago also EUVD-2026-6252
- cvss
- 3.6
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.1%
- EPSS 0.1% chance of exploitation in 30 days, percentile 0%
- public exploits
- 0
- none known
Summary
Proctorio Chrome Extension is a browser extension used for online proctoring. The extension contains multiple window.addEventListener('message', ...) handlers that do not properly validate the origin of incoming messages. Specifically, an internal messaging bridge processes messages based solely on the presence of a fromWebsite property without verifying the event.origin attribute.
Patch / fix
- Proctorio Secure Exam Proctor Extension 1.5.25220.36
Is CVE-2026-2345 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 8mo ago
Exploit prediction
0.08% chance of exploitation in the next 30 days, higher than 0% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 3.6 | CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N |
Affected products
- Proctorio Secure Exam Proctor Extension
Classification
- Weakness
-
- CWE-346 Origin Validation Error
References
Sources
- CVE List CVE-2026-2345
- NVD CVE-2026-2345
Fencer Intel 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.