TI-2026-70554 Aliases CVE-2026-108566 GHSA-j944-2cmv-5vxf

Cross-site scripting in InstantSoft icms2 Private Message handler

MEDIUM 56CWE-79Published 2026-10-11 · Updated 2026-10-13

Key facts

Attack vector: Network
Privileges required: Low
User interaction: Passive
Attack complexity: Low
Attack requirements: None
Impact type: Cross-site scripting, Code execution
Confidentiality · integrity · availability: None · Low · None
Fix status: No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79 and CWE-94.

Summary

InstantSoft icms2 versions up to and including 2.18.2 contain a cross-site scripting flaw in the Private Message Handler component. The index function does not neutralize the nickname argument before it is written into a web page (CWE-79). A remote attacker with low privileges can inject script that runs in a victim's browser when the victim interacts with the page. The exploit has been publicly disclosed and may be used.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

A vulnerability has been found in InstantSoft icms2 up to 2.18.2. This issue affects the function index of the file templates/default/controllers/messages/index.tpl.php of the component Private Message Handler. Such manipulation of the argument nickname leads to cross site scripting. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. The name of the patch is 3a1ec8fcb073a46d06a2ab83bc2bf68225834281. It is best practice to apply a patch to resolve this issue.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00241 15th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
instantsoft	icms2	2.18.0; 2.18.1; 2.18.2	—	No fix listed	CNA

icms2 Vendorinstantsoft Affected 2.18.0; 2.18.1; 2.18.2 Fixed in — No fix listed CNA

CPE names CNA · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:instantsoft:icms2::::::::	—	—	instantsoft

cpe:2.3:a:instantsoft:icms2:*:*:*:*:*:*:*:* Versions — — ·instantsoft

Remediation

The sources list no fixed version for icms2. The source description says to apply the patch 3a1ec8fcb073a46d06a2ab83bc2bf68225834281.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Timeline

2026-10-11 Threatist record created from CVE-2026-108566
2026-10-11 Alias added: GHSA-j944-2cmv-5vxf
2026-10-13 CISA SSVC decision points changed
2026-10-13 Priority changed: LOW → MEDIUM

References

Patch 1

https://github.com/instantsoft/icms2/commit/3a1ec8fcb073a46d06a2ab83bc2bf68225834281

Other 1

https://github.com/instantsoft/icms2/

TI-2023-03877 SQL Injection in instantsoft/icms2 CVSS 3.1CRITICAL 9.1
TI-2024-20589 SQL injection in index_chart_data action CVSS 3.1HIGH 7.2
TI-2023-04538 SQL Injection in instantsoft/icms2 CVSS 3.1HIGH 7.2
TI-2025-36697 InstantCMS vulnerable to Server-Side Request Forgery via package installer CVSS 3.1HIGH 7.2
TI-2023-04291 Cross-site Scripting (XSS) - Reflected in instantsoft/icms2 CVSS 3.1MEDIUM 6.1
TI-2026-39443 InstantCMS has Remote Code Execution in package installer CVSS 3.1MEDIUM 5.5

See all 25 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences