ShinHer Information Co., LTD. ShinHer StudyOnline System - Improper Authorization-2

published 2021-10-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-29305

cvss: 5.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 51%
public exploits: 0; none known

The “Study Edit” function of ShinHer StudyOnline System does not perform permission control. After logging in with user’s privilege, remote attackers can access and edit other users’ tutorial schedule by crafting URL parameters.

Exploit prediction

0.64% chance of exploitation in the next 30 days, higher than 51% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
NVD	2.0	5.5	AV:N/AC:L/Au:S/C:P/I:P/A:N

Affected products

ShinHer Information Co., LTD. ShinHer StudyOnline System

Classification

Weakness

CWE-285 Improper Authorization
CWE-862 Missing Authorization

References

twcert.org.tw /tw/cp-132-5201-dc534-1.html
third-party-advisory

Sources

CVE List CVE-2021-42331
NVD CVE-2021-42331

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