FluentCMS Blocks Plugin blocks cross site scripting

published 2026-06-06 5 mo ago modified 2026-07-23 3 mo ago also EUVD-2026-34969

cvss: 2.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits: 0; none known

A weakness has been identified in FluentCMS 0.0.5. The impacted element is an unknown function of the file /admin/blocks of the component Blocks Plugin. This manipulation causes cross site scripting. The attack may be initiated remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 5 mo ago (2026-06-08)

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

karinagante.github.io https://karinagante.github.io/cve-2026-11434/#proof-of-concept-poc referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	4.8	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
CNA	3.1	2.4	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA	3.0	2.4	CVSS:3.0/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA	2.0	3.3	AV:N/AC:L/Au:M/C:N/I:P/A:N/E:POC/RL:ND/RC:UR
CNA	4.0	1.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA	3.1	2.4	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N
CNA	2.0	3.3	AV:N/AC:L/Au:M/C:N/I:P/A:N

Affected products

n/a FluentCMS

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation
CWE-94 Improper Control of Generation of Code

References

karinagante.github.io /cve-2026-11434/#proof-of-concept-poc
exploit
vuldb.com /vuln/369014
vdb-entry
vuldb.com /vuln/369014/cti
signature, permissions-required
vuldb.com /cve/CVE-2026-11434
third-party-advisory
vuldb.com /submit/821094
third-party-advisory
karinagante.github.io /cve-2026-11434/
related
hackmd.io /@noka/BkHdIMFAWx
related

Sources

CVE List CVE-2026-11434
NVD CVE-2026-11434

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