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Fencer Intel
medium 4.8

CVE-2020-17451 json

flatCore before 1.5.7 allows XSS by an admin via the acp/acp.php?tn=pages&sub=edit&editpage=1 page_linkname, page_title, page_content, or p…

published 6y ago modified 4mo ago also EUVD-2020-9403

cvss
4.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

flatCore before 1.5.7 allows XSS by an admin via the acp/acp.php?tn=pages&sub=edit&editpage=1 page_linkname, page_title, page_content, or page_extracontent parameter, or the acp/acp.php?tn=system&sub=sys_pref prefs_pagename, prefs_pagetitle, or prefs_pagesubtitle parameter.

Patch / fix

  • flatcore flatcore 1.5.7

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Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • lists.openwall.net https://lists.openwall.net/full-disclosure/2020/08/07/1 referenced PoC, tagged "exploit" by a source, unverified
  • sec-consult.com https://sec-consult.com/en/blog/advisories/multiple-vulnerabilities-in-flatcore-cms/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 4.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N

Classification

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

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.