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Fencer Vulns
medium 6.1

CVE-2021-40637 json

OS4ED openSIS 8.0 is affected by cross-site scripting (XSS) in EmailCheckOthers.php.

published 2022-03-03 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27811

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 56%
public exploits
0
none known

Summary

OS4ED openSIS 8.0 is affected by cross-site scripting (XSS) in EmailCheckOthers.php. An attacker can inject JavaScript code to get the user's cookie and take over the working session of user.

Exploit prediction

0.79% chance of exploitation in the next 30 days, higher than 56% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/OS4ED/openSIS-Classic/issues/199 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

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.