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Fencer Intel
medium 6.5

CVE-2020-8439 json

Monstra CMS through 3.0.4 allows remote authenticated users to take over arbitrary user accounts via a modified login parameter to an edit…

published 6y ago modified 4mo ago also EUVD-2020-29306

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 75%
public exploits
0
none known

Summary

Monstra CMS through 3.0.4 allows remote authenticated users to take over arbitrary user accounts via a modified login parameter to an edit URI, as demonstrated by login=victim to the users/21/edit URI.

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Exploit prediction

1.59% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • uploadboy.me http://uploadboy.me/cn40ne6p89t6/POC.mp4.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Classification

Weakness

References

Sources

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.