CVE-2026-86244: FastAdmin advisory

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

What it is

A security vulnerability has been detected in FastAdmin up to 1.2.0.20210401_beta. Affected is the function register/login of the file application/index/controller/User.php of the component User Controller. Such manipulation of the argument url leads to cross site scripting. The attack may be performed from remote. The exploit has been disclosed publicly and may be used. Upgrading to version 1.2.1.20210731_beta is able to address this issue. The name of the patch is b3d32e2bf3637488cfe2fc58a27a9d2475b2b51b. It is recommended to upgrade the affected component.

Description quoted from the CVE record (assigned by VulDB, published 2026-09-07).

Weakness: Cross Site Scripting; Code Injection

How it can be exploited

Exploitable over the network with low attack complexity with no special attack requirements needing no privileges and a user must take an action. Impact: confidentiality none, integrity low, availability none. CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P

CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: no. Technical impact: partial.

Public exploit evidence (Exploit Observer)

Exploit Observer found 5 code repositories naming this CVE.

Code repositories that name a CVE are often scanners, copies or fakes, and some are malware. Read the code before running anything.

See all 8 references on Exploit Observer

Live scores

EPSS: 0.005
low predicted chance of attack
VEDAS: 0.985
strong exploit evidence
On CISA KEV: Not listed
Detection rule: Nuclei · Suricata

Who is affected

Product	Affected	Not affected
FastAdmin	version 1.2.0.20210401_beta	1.2.1.20210731_beta is not affected

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

Vendor guidance:

https://github.com/fastadminnet/fastadmin/commit/b3d32e2bf3637488cfe2fc58a27a9d2475b2b51b (patch)

How to detect it

Nuclei template (active check)

FastAdmin - Reflected Cross-Site Scripting
FastAdmin up to 1.2.0.20210401_beta is vulnerable to unauthenticated reflected Cross-Site Scripting in the User controller (application/index/controller/User.php). The register and login actions read the ‘url’ request parameter with only a trim() filter and emit it into the value attribute of a hidden input without HTML encoding, so a crafted value closes the attribute and injects arbitrary markup that executes in the victim’s browser. This template reflects an inert payload to prove the injection.

Name and description quoted from the template, written by VEDAS.

The template sends 2 requests (GET /index/user/register.html?url=vedasINJ%22%3E%3Csvg/onload=alert(1)%3E, GET /index/user/login.html?url=vedasINJ%22%3E%3Csvg/onload=alert(1)%3E); it decides using status, word matchers. Severity in the template: medium. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash

nuclei -u https://your-host -t CVE-2026-86244.yaml

Show the template (45 lines)

yaml

id: CVE-2026-86244

info:
  name: "FastAdmin - Reflected Cross-Site Scripting"
  author: vedas-arpsyndicate
  severity: medium
  description: |
    FastAdmin up to 1.2.0.20210401_beta is vulnerable to unauthenticated reflected Cross-Site Scripting in
    the User controller (application/index/controller/User.php). The register and login actions read the
    'url' request parameter with only a trim() filter and emit it into the value attribute of a hidden input
    without HTML encoding, so a crafted value closes the attribute and injects arbitrary markup that executes
    in the victim's browser. This template reflects an inert payload to prove the injection.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-86244&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=fastadmin&match=exact
  classification:
    cvss-metrics: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
    cvss-score: 2.1
    cve-id: CVE-2026-86244
    cwe-id: CWE-79
  metadata:
    verified: false
  tags: cve,cve2026,fastadmin,xss,reflected
http:
  - method: GET
    path:
      - "{{BaseURL}}/index/user/register.html?url=vedasINJ%22%3E%3Csvg/onload=alert(1)%3E"
      - "{{BaseURL}}/index/user/login.html?url=vedasINJ%22%3E%3Csvg/onload=alert(1)%3E"

    stop-at-first-match: true
    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - 'vedasINJ"><svg/onload=alert(1)>'

      - type: word
        part: content_type
        words:
          - "text/html"

      - type: status
        status:
          - 200

CVE-2026-86244.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-86244 FastAdmin - Reflected XSS via url parameter. Add them to your Suricata rule set and reload.

Show the rules

suricata

# CVE-2026-86244 - FastAdmin <= 1.2.0.20210401_beta reflected XSS via the 'url'
# parameter of the index/user register and login actions (User.php). The value is
# echoed unencoded into a hidden input value attribute. Matches the unauthenticated
# GET carrying a script payload in url=.
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2026-86244 FastAdmin - Reflected XSS via url parameter"; flow:established,to_server; http.uri; content:"/index/user/"; nocase; fast_pattern; content:"url="; nocase; pcre:"/url=[^&]*(?:<|%3c)svg[^&]*onload/i"; classtype:web-application-attack; reference:cve,CVE-2026-86244; reference:url,https://www.exploit.observer/?keyword=CVE-2026-86244&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=fastadmin&match=exact; sid:1098001; rev:1;)

CVE-2026-86244.rules on GitHub

References

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.