CVE-2026-27964Public exploit

Script execution via unencoded fsNick cookie

Published May 18, 2026 · Updated May 18, 2026

Reflected XSS in FacturaScripts 2025.7 and earlier allows local users to execute script through a crafted fsNick cookie. The auth methods in Core/Base/Controller.php and Core/Template/Controller.php place the unencoded cookie value in warning output that reaches the HTML response. Exploitation requires a valid low-privileged account, control of its browser cookie, and a page load; the script runs before forced logout and can perform one unauthorized action.

CVSS severity3.9
Low
EPSS probability0.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in FacturaScripts 2025.7 and earlier allows local users to execute script through a crafted fsNick cookie. The auth methods in Core/Base/Controller.php and Core/Template/Controller.php place the unencoded cookie value in warning output that reaches the HTML response. Exploitation requires a valid low-privileged account, control of its browser cookie, and a page load; the script runs before forced logout and can perform one unauthorized action.

The record

CVE
CVE-2026-27964
Published
May 18, 2026
Updated
May 18, 2026
Vendor
FacturaScripts
Product
FacturaScripts
Classifications
CWE-79, T1203
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 18, 2026CVE publishedPublication date reported by the CVE source.
  2. May 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2025.8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

FacturaScripts · FacturaScriptsversion=< 2025.8

Published CVSS scores

3.9GitHubCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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