CVE-2026-2345 | Insufficient Origin Validation in Proctorio Chrome Extension postMessage Handlers

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.

Published: 2026-02-11 Last update: 2026-04-15 Assigner: 7004884b-51e2-48e8-b4a2-5ca29e80453e Source: 7004884b-51e2-48e8-b4a2-5ca29e80453e
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-2345 is rated Low Risk (14.5/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.01%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-2345

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-02-12 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-2345

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.6 3.1 LOW
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 1.0 2.5 7004884b-51e2-48e8-b4a2-5ca29e80453e

Weakness enumeration for CVE-2026-2345

Affected software / configurations for CVE-2026-2345

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-2345

cvelogic Threat Intelligence